FAX CLASS 1 OPERATION


FAX I/O PROCESSING

The fax I/O interface supports asynchronous serial and parallel interfaces. The 
interface rate is 19200 bps. Start and stop elements are removed from the 
transmit data, and added to the receive data.  Bot transmit and receive data is 
buffered. Flow control using XON/XOFF (DC1/DC3) or RTS/CTS is provided.

Unique control character string are identified, filtered, or reinserted into 
the I/O data stream. These control characters and their resultant action are 
descrobed below.


DTE to Modem Transmit Data Stream

Characters Detected			Action Taken

<DLE><data>				Delete <DLE><data> characters
<DLE><ETX>                              Recognized as a string
                                        terminator, and take
                                        appropriate action
<DLE><DLE>                              Replace with single <DLE> character.


Modem to DTE Recieve Data Stream

Characters Detected			Action Taken

<DLE>					Insert extra <DLE> ahead of <DLE>.

The modem also identifies the end of a frame by inserting <DLE><ETX> into the 
data stream after the FCS bytes.


Fax Origination

Origination of fax calls is made using the ATD command. Upon completion of the 
dial function, a calling tone at 1100 Hz, with a cadence of 0.5 seconds ON, and 
3 seconds off is transmitted. The modem automatically enters mode +FRH=3 and 
sends the CONNECT message to the DTe when FSK flags are detected from the 
remote.


Fax Answering

Answering of fax calls is identical to the answering of data calls with the 
exeption that the modem enters the fax hanfshaking mode instead of the data 
handshaking mode after going off-hook. If +FAE=0, the modem, after sending 
answer tone, automatically enters fax mode (+FTH=3), sends the CONNECT message 
to the DTE, and starts sending the FSK flags. If FAE=1, the modem determines if 
the caller is a data modem or a fax modem and sends the DATA or FAX result 
code, respectively, to the DTE.



Table 2-1 Fax Class 1 Commands

Command					Function

Service Class ID
	+FCLASS=				Service Class

Fax Class 1 Commands
	+FTS=n					Stop Transmission and Wait
	+FRS=n					Receive Silence
	+FTM=n					Transmit Data
        +FRM=n                                  Receive Data
        +FTH=n                                  Transmit data with HDLC Framing
	+FRH=n					Receive Data with HDLC Framing


Fax Control Transmission

Fax control transmission is initiated by the AT+FTH=n command. After this 
command is issued, the modem generates the CONNECT message and transmits 
carrier in the modulation scheme specified by the parameter n. The modem then 
transmits HDLC flags for a minimum of 1 second. The modem continues to transmit 
the HDLC flags until it receives a character from the DTE.

When characters are received from the DTE, the modem adds start and end flags, 
performs zero bit insertion, generates FCS, and deletes <DLE><chr> character 
pairs before transmitting the characters to the remote fax machine.. Each 
<DLE><DLE> sequence is transmitted as a single <DLE>. <DLE><ETX> is considered 
as the end of frame marker and is not transmitted. All data received from the 
DTE after <DLE><ETX> is ignored by the modem until the modem either generates 
the CONNECT, OK, or ERROR result code.

If no more data is in the transmit buffer and the final bit was a 1(bit 4 of 
the second byte received from the DTE), the modem generates the OK result code 
and returns to he command mode. If the final bit was a 0, the modem generates 
the CONNECT message and waits for further data from the DTE while transmitting 
HDLC flags. If no more data is received before 5 seconds elapse, the modem 
drops carrier, goes on-hook, and generates the ERROR result code.


Fax Control Reception

Fax control recetion is initiates using the AT+FRH=n command. After this 
command is issued, the modem looks for carrier in the modulation scheme 
specified by the parameter n. If no carrier id detected before the period of 
time specified in the register S7 expires, the modem generates a NO CARRIER 
message and returns to command mode. If carrier is detected that is not the one 
specified by the parameter n, the modem generates the +FCERROR message and 
return to the command mode. If the specified carrier is detected, the modem 
generates the CONNECT  message and enter the  HDLC receive mode, the modem 
receives the HDLC frames from the remote fax machine, strips the flags, 
performs zero-bit deletion, performs error checking, and handles <DLE><chr> 
character pairs before passing the data to the DTE. The modem prefixes each 
<DLE> character with another <DLE> character before sending it to the DTE. 
After the last byte in the frame, the modem sends <DLE><ETX> to the DTE marking 
the end of the frame. The modem then generates either the OK message if no 
errors were detected or the ERROR message if error were detected (FCS is 
incorrect), and returns to command mode.

While in command mode, the modem continues to receive data in the selected 
modulation scheme, and sends the data after sending the CONNECT message to the 
DTE when the DTE reissues the +FRH command with the same parameter. If the DTE 
issues the +FRH command with a different parameter, the modem clears all 
buffers and proceeds as described previously.


If carrier is lost while in command mode and the DTE reissues the +FRH command 
with the same parameter, and there is no data in the buffer, the modem sends 
the ERROR result code to the DTE and returns to the command mode. If there is 
data in the buffer, the modem sends the next frame of buffered data to the DTE, 
followed by <DLE><ETX>, and either the ERROR result code if error were detected 
or the OK result code if no errors were detected. The mode then returns to 
command mode.

The modem concludes an error is detected if the carrier is lost for any period 
of time during or before the reception of a frame. If the carrier is lost for a 
time period longer than the time specified by the register S10, the modem 
finishes delivering the data in the receive buffer (if any) to the DTE, sends 
<DLE><ETX>, generates the ERROR message, and returns to command mode.. All 
subsequent data received from the remote is discarded.

If the modem detects the frame abort sequence (seven consecutive ones with no 
zero insertion) while it is waiting for the frame beginning flag (it was 
receiving HDLC flags), it will wait for the HDLC flags again until either 
carrier is lost, or the DTE aborts the process by sending an abort character or
by dropping DTR with &D2 in effect. If the frame abort sequence is detected 
while the modem is receiving a frame it finishes delivering the data in the 
receive buffer (if any) to the DTE, sends <DLE><ETX>, generates the ERROR 
message, and returns to command mode. The modem keeps looking for the HDLC 
flags followed by more data from the remote, with the selected modulation 
scheme.

If the modem detects a receive buffer overflow condition, it concludes that 
there was a  FCS error in that frame. The modem will receive more frames only 
if the starting flag is detected and there is room in he receive buffer. If a 
starting flag is detected and there is no room in the buffer, the modem 
discards all data in the frame.

If the modem receives any characters from the DTE after the +FRH command 
(except flow control characters if software flow control is in effect), or if 
the modem detects a high-to-low transition of the DTR signal while &D! is in 
effect, it sends <DLE><ETX> to the DTE, generates OK result code, and returns 
to command mode.. The receive buffer is cleared and all the data received from 
the remote is discarded. If the modem detects a DTR drop while &D2 is in 
effect, ir goes on-hook, sends <DLE><ETX> to the DTE, generates OK result code, 
and returns to command mode. If the modem detects a DTR drop while &D3 is in 
effect, the modem performs a warm reset.


Fax Data Transmission

Fax data transmission is initiated by the AT+FTM=n command. AFter this command 
is issued, the modem generates the CONNECT message and transmits carrier in the 
modulation scheme specified in the parameter n. The modem then transmits 
constant 1 bits for a minimum of one second and continues to transmit constant 
1 bits until it receives a character from the DTE.

When data is received from the DTE, the mode deletes start and stop bits and 
deletes all <DLE><chr> character pairs before transmitting the data to the 
remote. Each <DLE><DLE> sequence is transmitted as a single <DLE>. <DLE><ETX> 
is considered as the end of stream marker, and is not transmitted. All data 
received from the DTE after the <DLE><ETX> is ignored by the modem until the 
modem generates either the CONNECT, OK, or ERROR result code.

If no more data is in the transmit buffer, and the last transmitted character 
was not an ASCII NULL, the modem generates the OK result code and returns to 
the command mode. If the last character transmitted was an ASCII NULL, the 
modem generates the CONNECT message to the DTE and waits for further data from 
the DTE while transmitting NULLs to the remote. If no more data is received 
before 5 seconds elapse, the modem continues to transmit the data described in 
the previous paragraph. If five seconds elapse and no more data is received 
from the DTE, the modem drops carrier, goes on-hook, and generates an ERROR 
result code.


Fax Data Reception

Fax data reception is initiated using the AT+FRM=n command. After this command 
is issued, the modem looks for the carrier in the modulation shceme specified 
by the parameter n. If no carrier if detected before the period of time 
specified by the register S7 expires, the modem generates the NO CARRIER 
message and returns to command mode. If carrier is detected and is not the one 
specified by the parameter n, the modem generates the +FCERROR message and 
returns to the command mode. If the specified carrier is detected, he modem 
generates the CONNECT message and enters the data receive mode.

While in data receive mode, the modem receives data from the remote, adds start 
and stop bits, and handles <DLE><chr> character pairs before passing the data 
to the DTE. The modem prefixes each <DLE> character with another <DLE> 
character before sending it to the DTE.

If the carrier is lost for a time period longer than the time specified by the 
register S10, the modem finishes delivering data in the receive buffer (if any) 
to the DTE, sends <DLE><ETX>, generates the NO CARRIER result code, and returns 
to the command mode. All subsequent data received from the remote is discarded.

If the modem detects a receive buffer overflow condition, it stops receiving 
from the remote until there is room in the receive buffer.  The modem informs 
the DTE of the buffer overflow after it sends to the DTE the last character 
that was stored in the buffer before the overflow occured.


If the modem receives any character from the DTE after the +FRM command (except 
flow control characters if software flow control is in effect), or if the modem 
detects a high-to-low transition of the DTR signal while &D1 is in effect, it 
sends <DLE><ETX> to the DTE, generates the OK result codes, and returns to 
command mode.. The receive buffer is cleared and all data received from the 
remote is discarded. If loss of DTR is detected while &D2 is in effect, the 
modem goes on-hook, sends <DLE><ETX> followed by OK result code to the DTE, and 
returns to command mode. If the modem detects a DTR drop while &D3 is in 
effect, the modem performs a warm reset.


Table 6-2. Fax Class 1 Command Definitions

Command				Description

+FCLASS=n               Select Service Class. +FCLASS=n commans sets
                        the active service class.
			Parameters	: 0-2
			Default		: 0
			Command options:
				+FCLASS=0	Select Data Mode
				+FCLASS=1	Selects Facsimile Class 1
				+FCLASS=2	Selects Facsimile Class 2

+F<command>?            Report Active Configuration. +F<command>?
                        interrogates the modem to
			determine the active configuration.
			Typical responses are:
				+FAE=?		0, 1
				+FCLASS=?	0, 1, 2
				+FTM=?		3, 24, 48, 72, 96 (RC96AC)
                                +FRM=?       3, 24, 48, 72, 96 (RC96AC)
                                +FTM=?          3, 24, 48, 72, 96,
                                                97, 98, 121, 122, 145, 146 (RC144AC)

				+FRM=?	3, 24, 48, 72, 96, 97, 98, 121, 122, 145, 146
						(RC144AC)

+FAEn                   Data/Fax Auto Anwer. +FAEn allows the DTE to
                        either restrict answer to Class 1, or to
                        automatically detect whether the calling
                        station is a fax class 1 modem or data modem,
                        and answer accordingly.
			Parameters	: 0, 1
			Default		: 0
			Command Options:
                                n = 0   Disable data/fax auto answer
                                        mode (default). The modem
                                        answers a fax modem only.
                                n = 1   Enable data/fax auto answer
                                        mode. The modem answers as a
                                        fax or data modem.

+FTS=n                  Stop Transmission and Wait. +FTS=n causes the
                        modem to terminate and wait  for n 10
                        milliseconds interval before responding with
                        the OK result code. An ERROR response code
                        results if this command is issued while the
                        modem is on-hook.

+FRS=n                  Receive Silence. +FRM=n causes the modem to
                        report back to the DTE with an OK result code
                        after n 10 millisecond of silence have been
                        detected on the line. This command is aborted
                        if any character is received from the DTE.
                        The modem discards the aborting character and
                        issues an OK result code. An ERROR response
                        code results if this command is issued while
                        the modem is on-hook.

+FTM=n                  Transmit Data. +FTM=n causes the modem to
                        transmit data using the modulation defined
                        below. An ERROR response code results if this
                        command is issued while the modem is on-hook.
			Parameters	:
			Command options:
				+FTM=3		V.21 ch.2 300 bps
				+FTM=24	V.27 ter 2400 bps
				+FTM=48	V.27 ter 4800 bps
				+FTM=72	V.29 7200 bps
				+FTM=96	V.29 9600 bps
				+FTM=73	V.17 7200 bps long
				+FTM=74	V.17 7200 bps short
				+FTM=96	V.29 9600 bps
				+FTM=97	V.17 9600 bps long
				+FTM=98	V.17 9600 bps short
				+FTM=121	V.17 12000 bps long
				+FTM=122	V.17 12000 bps short
				+FTM=145	V.17 14400 bps long
				+FTM=146	V.17 14400 bps short

+FRM=n          Receive Data. +FRM=n causes the modem to enter the
                receiver mode using the modulation defined below. An
                ERROR response code results if this command is issued
                while the modem is on-hook.
		Paramters: see Command options
		Command options:
			+FRM=3	V.21 ch.2 300 bps
			+FRM=24	V.27 ter 2400 bps
			+FRM=48	V.27 ter 4800 bps
			+FRM=72	V.29 7200 bps
			+FRM=73	V.17 7200 bps long
			+FRM=74	V.17 7200 bps short
			+FRM=96	V.29 9600 bps
			+FRM=97	V.17 9600 bps long
			+FRM=98	V.17 9600 bps short
			+FRM=121	V.17 12000 bps long
			+FRM=122	V.17 12000 bps short
			+FRM=145	V.17 14400 bps long
			+FRM=146	V.17 14400 bps short

+FTH=n          Transmit data with HDLC Framing. +FTH=n causes the
                modem to transmit data using HDLC protocol and the
                modulation defined below. An ERROR response code
                result if this command is issued while the modem is
                on-hook
		Parameters:	See Command options.
		Command options:
			+FTH=3		V.21 Channel 2 300 bps
			+FTH=24	V.27 ter 2400 bps
			+FTH=48	V.27 ter 4800 bps
			+FTH=72	V.29 7200 bps
			+FTH=73	V.17 7200 bps long
			+FTH=74	V.17 7200 bps short
			+FTH=96	V.29 9600 bps
			+FTH=97	V.17 9600 bps long
			+FTH=98	V.17 9600 bps short
			+FTH=121	V.17 12000 bps long
			+FTH=122	V.17 12000 bps short
			+FTH=145	V.17 14400 bps long
			+FTH=146	V.17 14400 bps short

+FRH=n          Receive Data with HDLC Framing. +FRH=n causes the
                modem to recieve frames using HDLC protocol and the
                modulation defined below. An ERROR response error
                results if this command is issued while the modem is
                on-hook,
		Parameters	: see Command option
		Command options:
			+FRH=3		V.21 Channel 2 300 bps
			+FRH=24	V.27 ter 2400 bps
			+FRH=48	V.27 ter 4800 bps
			+FRH=72	V.29 7200 bps
			+FRH=73	V.17 7200 bps long
			+FRH=74	V.17 7200 bps short
			+FRH=96	V.29 9600 bps
			+FRH=97	V.17 9600 bps long
			+FRH=98	V.17 9600 bps short
			+FRH=121	V.17 12000 bps long
			+FRH=122	V.17 12000 bps short
			+FRH=145	V.17 14400 bps long
			+FRH=146	V.17 14400 bps short






FAX CLASS 2 OPERATION

COMMAND SYNTAX AND GUIDELINES



DTE Commands

The ISO character set (T.50 International Alphabet 5, American Standard Code 
for Information interchange) is used for the issuance of commands and 
responses. Only the low-order 7 bits of each character are used for commands 
and parameters; the high order bit is ignored. Upper case characters are 
equivalent to lower case characters.

For Phase C data transmission or reception, all 8 bits are needed.


DTE Command Lines.

A command line is a string of characters sent from a DTE to the DCE while the 
DCE is in the command state. Command lines have a prefix, a body, and a 
terminator. The prefix consists of the ASCII character "AT" (065, 084) or "at" 
(097, 116) The body is a string of commands restricted to printed ASCII 
characters, (032-126).  Space character (ASCII 032) and control characters 
other than CR (ASCII 013) and BS (ASCII 010) in the command string are ignored. 
The default terminator is the ASCII <CR> character. Characters that precede the 
AT prefix are ignored.


Basic Command Syntax.

Characters within the command line are sparsed as commands with associated 
parameter values.  The basic command consist of single ASCII character, or 
single characters preceded by a prefix character (e.g., "&"), followed by a 
decimal parameter.

Midding decimal parameters are evaluated as 0.


Extended Command Syntax

The facsimile commands use extended syntax. The are preceded by the "+F" 
characters, and they are terminated by the semicolon ":" character (ASCII 059) 
or by the <CR> that terminated the command line.

	AT+FAE=0	; +FCR 1 <CR>

This command instructs the DCE to answer automatically a data or fax call and 
also enables reception.

	AT+FCLASS=0 <CR>	for Data mode
	AT+FCLASS=1 <CR>	for Service Class 1 Fax
	AT+FCLASS=2 <CR>	for Service Class 2 Fax

In Class 2, the DCE makes ans terminates calls, manages the communication 
session and negotiates (T.30 protocol) and transports the image data to DTE. 
The T.4 protocol management of image data, etc. is done by DTE.

The response to
	AT+FCLASS=0 <CR>	in Data Mode
or
	AT+FCLASS=2 <CR>	in Service Class 2 Fax
is
	OK

The service class may be set by the DTE from the choices available using the 
"+FCLASS=<VALUE>" command.

General Rules

1.      +Fnnn commands must be entered completely otherwise an ERROR
        response is sent.
2.      All response messages are preceded and followed by <CR><LF>.
        Multiple response commands, e.g., +FDIS: +FCSI: and +FDCS:
        will therefore appear to have a blank line between them.
3.      Fax CLass 2 commands can be seperated by ":" character. The
        ";" can be omitted if desired. Note that non-data commands
        cannot be seperated by the ":" character. The ";" can be
        omitted if desired. Note that non-data commands cannot be
        seperated by ";" which is allowed as a dial modifier.
4.      All Class 2 commands are assumed to be the final command on
        the command line.  Additional characters will be ignored.
5.      An ERROR message will be generated if any of the following
        conditions:
	a.	A Class 1 command is received while in Class 2.
	b.	A Class 2 command is received while in Class 1.
        c.      A Class 1 or Class 2 action command is received while
                in data modem mode.
        d.      A Class 2 read-only parameter is given the "=" form
                of a +F command (e.g., AT+FAXERR=5).
        e.      A Class 2 action command is given the inappropriate
                "=" or "=?" form (e.g., AT+FDT=?).


Serial Port Speed and Flow Control.

During fax mode, the DTE-DCE port speed is 19200 bps.

The DCE provides a peed buffer of 1024 bytes and provides DC1/DC3 (XON/XOFF) or 
RTS/CTS method of controlling the data into the buffer.  This flow control is 
controlled by AT&K3 command.

This method of data flow control is available only for DTE to DCE direction of 
data. There is no provision for data flow control from DCE to DTE.



Data Stream Termination.

The DCE exchanges streams of data with the DTE while executing data transfer 
commands.

The ASCII <DLE> character (016) is used as a special  character, to sheild 
special characters. The <DLE><ETX> character pair (<106><003>) is used to mark 
the end of a stream. The following patterns are used:
	any data...<DLE><ETX>		end of stream
	any data...<DLE><DLE>		single <DLE> in data
        any data...<DLE><any byte>      delete<DLE><any byte>


DTE to DCE Streams.

The DCE filters the data stream from the DTE, and removes all characters pairs 
beginning with <DLE>. The DCE recognizes <DLE><ETX> as the stream terminator. 
The DCE recognizes <DLE><DLE> and reinserts a single <DLE> in its place.

The DTE must filter stream data to the DCE, and insert extra <DLE> characters 
ahead of data.


DCE to DTE Streams.

The DTE must filter the data stream from the DCE, and remove all character 
pairs beginning with <DLE>. The DTE must recognize <DLE><ETX> as the stream 
terminator. The STE must recognize <DLE><DLE> and reinsert a single <DLE> in 
its place.

The DCE filters stream data to the DTE, and inserts extra <DLE> characters 
ahead of data.


Auto Answer.

The DCE can answer as a data DCE or as a fax DCE. It can answer the call 
adaptively, i.e., it can determine whether call is 'data' or 'fax'. The +FAA 
parameter controls this feature.

        AT+FAA=1        ; Auto answer as a facsimile or a data modem
                          depending on call
	CONNECT xxxx	; DCE status response if data call
	+FCON		; DCE status response if fax call


Identification of T.30 Options.

Group 3 devices negotiate session parameters in DIS, DCS and DTC frames.


Session Status Reporting

The DCE provides reports to the DTE on the status of a session. The DCE 
provides following status reports:

	1.	Connection and hang up status:
			+FCON
			+FHNG:<0-255>
        2.      Requested DIS session parameters +FDIS:<string>
                reports remote facsimile capabilities:
			syntax: +FDIS: VR, BR, WD, LN, DF, EC, BF, ST
	3.	+FDCS: <string> reports the negotiated parameters
	4.	Phase C prompts:
			XON, XOFF, DC2
        5.      Phase C base status reports: depending upon copy
                quality  and related end-of page status:
			+FPTS: <1-5>


Procedure Interrupt Negotiation

CCITT allows a station to request a procedure interruption at the end of a 
page. This request is passed between station by the PIP, PIN and PRI-Q 
messages.



SERVICE CLASS 2 IDENTIFICATION AND SELECTION

The fax Class 2 commands are summarized in table3-1

Three commands report identification and selection information. Each of these 
three commands cause the DCE to send a message to the DTE.  The messages reside 
in the EPROM starting at ROM address 2002h (ROM bank 3 address 8002h) and can 
be modified by the OEM. Each message is 20 bytes (ASCII encoded) followed by 
the terminating character (binary 0). If any message is modified, the firmware 
checksum must be recalculated and stored at address ROM address 8000h (ROM bank 
0 address 8000h).


+FMFR?, Request Manufacturer Identification

The +FMFR command causes the DCE to send a message identifying the DCE product 
manufacturer. The message starts at address 8002h. The binary terminator is 
located at address 8015h. The default message is:
	ROCKWELL
	OK


+FMDL?, Identify Product Model

The +FMDL? causes the DCE to send a message identifying the DCE product model. 
The message starts at address 8016h. The binary terminator is located at 
address 802Ah. The default message is
	V.32AC
	OK


+FREV?, Identify Product Revision

The +FREV? command causes the DCE to send a message identifying the DCE product 
product model revision number. The message starts at address 802Bh in EPROM. 
The binary terminator is located at address 803FEh. The typical default message 
is:
	V0.200_TR14-JXXX-001
	OK


SERVICE CLASS 2 ACTION COMMANDS

These commands transfer data, and punctuate sessions. They also release 
specific T.30 messages. All action commands must be the last command on the 
command line. This is indicated by the terminating <CR>.

All action commands initiate processes. The modem will not accept other 
commands from the DTE until the modem issues a final result code (e.g., OK, 
CONNECT). The modem will abort the process if it receives any character before 
the final result code is issued.


Table 3-1 Fax Class 2 Commands

Command				Function

Service Class ID
	+FCLASS=			Service Class

Class 2 Acrion Commands
	D				Originate a Call
	A				Answer a Call
	+FDT=				Data Transmission
        +FET=N                          Transmit Page Punctuation
	+FDR				Begin or Continue Phase C Receive Data
	+FK				Session Termination

Class 2 DCE Responses
	+FCON				Facsimile Connection Response
	+FDCS:				Report Current Session
	+FDIS:				Report Remote identification
	+FCFR				Indicate Confirmation to Receive
	+FTSI:				Report the Transmit Station ID
	+FCSI:				Report the Called Station ID
	+FPTS:				Page Tranfer Status
	+FET:				Post Page Message Response
	+FHNG				Call Termination With Status

Class 2 Session Parameters
	+FMFR?			Identify Manufacturer
	+FMDL?			Identify Model
	+FREV?			Identify Revision
	+FDCC=			DCE Capabilities Parameters
	+FDIS=				Current Sessions Parameters
	+FDCS=			Current Session Results
	+FLID=				Local ID String
	+FCR				Capability to Receive
	+FPTS=				Page Transfer Status
	+FCR=				Capability to Receive
	+FAA				Adaptive Answer
	+FBUF?				Buffer Size (Read Only)
	+FPHCTO			Phase C Time Out
	+FAXERR			Fax Error Value
	+FBOR				Phase C Data Bit Order



ATD, Originate a Call

Syntax	: ATD....<CR>

The DCE can support a DTE command to originate a call using the ATD command

If this command is unsuccessful, the DCE reports an appropriate failure or 
error type result code such as NO CARRIER, NO DIALTONE, or BUSY

If this call is successful, the typical DCE response is:
	ATDnn..nn	(go off-hook, dial, get CED)
	+FCON		(DCE detects flags)
	[+FCSI:<remote ID string>]
	+FDCS:<T.30 subparameter string>
	OK

The DCE dials, detects call progress and generates the CNG tone. Then it waits 
for a DIS frame. On detection of the first Phase B preamble (V.21 ch.2 
modulated by 300 bit/s HDLC flags) it reports the "+FCON" message to the DTE. 
The DCE then switches to 19.2K bps.

The DCE generates a DCS frame based on the received DIS frame and on the 
previously set +FDIS parameter. A +FDT command from the DTE releases the DCE to 
transmit that DCS frame.

The DCE reports the initial received T.30 negotiation messages, including the 
DIS frame and the optional CSI ID string. The +FDIS:  report is followed by the 
OK final result code.


ATA, Answer a Call

The DCE can support a DTE command to answer an incoming call using the ATA 
command.

The DTE may issue an Answer command in response to an incoming ring.

If the Answer command is unsuccessful, the DCE will report an appropriate 
failure or error type result code, such as NO CARRIER.


Manual Call Answer

If this call is successful, the typical DCE response (answer and receive) is:
	+FCON
	[+FTSI:<remote ID string>]
	+FDCS:<T.30 subparameter string>
	OK
	(DTE should issue +FDR command here)

On receipt of an Answer command from the DTE, the DCE answers and generates the 
CED tone. The DCE then gererates a DIS frame (derived from the +FDIS parameter) 
and hunts for the first T.30 negotiation frames. On detection of the first 
Phase B preamble (V.21 ch 2 modulation by 300 bit/s HDLC flags), it reports the 
"+FCON" message to the DTE.

The DTE should report the initial received T.30 negotiation messages, including 
the DCS frame. The +FDCS: report will be followed by the OK final result code.


Automatic Answer

The modem provides for automatic answering of incoming calls. If configured for 
automatic answer, the modem answers an incoming call in compliance  with T.30, 
and reports the same messages as described for manual answer.


Connection as a Data Modem

If configured to do so by the +FAA parameter, the DCE will adaptively answer as 
a facsimile DCE or as a data DCE. If the DCE answers as a data DCE, it resets 
the +FCLASS parameter to 0 and issues the appropriate final result code (e.g., 
CONNECT or NO CARRIER) to the DTE.


+FDT, Data Transmission

Syntax	: +FDT<CR>

The +FST command prefixes Phase C data transmission. When the DCE is ready to 
accept Phase C data, it issues the negotiation responses and the CONNECT result 
code to the DTE.

In Phase B, the +FDT command releases the DCE to proceed with negotiation, and 
release the DCS message to the remote station. In Phase C, the +FDT command 
resumes transmission after the end of a prior transmit data stream.


Initiate Page Transmission

Phase B DCE polled response:
	[+FCSI:<remote ID string>]	-if new CSI received
	[+FDIS:<subparameters from remote station>]	-if new DIS received
	+FDCS:<T.30 subparameter string>
	CONNECT
	<XON>				-when ready for data

After placing a call, or after finishing a document exchange, the DTE may 
command the DCE to re-enter T.30 Phase B to attempt to  negotiate a document 
transmission.


Continue a Page

	CONNECT
	<XON>

The DTE may issue more than one +FDT command for a given page, so that 
different files may be concatenated together. These files must have the same 
format.


Phase C Data Framing

Phase C data must be presented to the DCE in stream mode. The DCe expects the 
Phase C data to flow until it detects <DLE><ETX> termination characters. The 
DCE will filter the stream.

The DCE will acknowledge the end of the data by returing the OK result code to 
the DTE.

If there is data underrun before the next +FDT or +FET= command, the DCE will 
zero-fill pad as per T.4 until the Phase C timeout (+FPHCTO) is reached, or 
until more data is received. The DCE appends an RTC pattern to the transmit 
data after an +FET= command is received from the DTE.


Phase C Data Format

The Phase C data format will be of the format specified by the negotiated T.30 
DCS frame.

The DCE will use the negotiated minimum Scan Time parameter from the DCS frame, 
and insert sufficient fill bits to pad each line to the minimum scan time. This 
is reported in the +FDCS:ST subparameter.

If the DCE finds more than one consecutive EOL in Phase C data (e.g., RTC), it 
will send only one EOL.

Note 1:	Phase C data must conform to T.4 specifications.
Note 2:	The DTE need not include a final RTC in response to an FET = command.
Note 3: 	Some facsimile machines may treat two EOLs as an RTC.




Table 3-2 T.30 Session Subparameter Codes

Label  Function                Value           Description

VR     Vertical                        0       Normal, 98 dpi
       Resolution              1               Fine, 196 dpi

BR     Bit Rate                        0       2400 bits/s V.27 ter
       (See Note 1)            1               4800 bits/s V.27 ter
                               2               7200 bits/s V.29 or V.17
                               3               9600 bits/s V.29 or V.17
                                   **4         12000 bits/s V.33 or V.17
                                   **5         14400 bits/s V.33 or V.17

WD     Page Width              0               1728 pixels in 215 mm
                               1               2048 pixels in 255 mm
                               2               2432 pixels in 303 mm
                                     *3          1216 pixels in 151 mm
                                     *4          864 pixels in 107 mm

LN     Page Length             0               A4, 297 mm
                                     *1          B4, 364 mm
                                     *2          unlimited length

DF     Data Compression        0               1 - D modified Huffman
       Format                  1               2 - D Modified read
                                     *2          2 - D uncompressed mode
                                     *3          2 - D modified modified read

EC     Error Correction                0         Disable ECM
       (Annex A/T.30)                *1          Enable ECM, 64 bytes/frame
                                     *2          Enable ECM, 256 bytes/frame

BF     Binary File Transfer    0               Disable BFT
                                     *1          Enable BFT

ST     Scan Time/Line                          VR = normal VR = fine
                               0               0 ms     0 ms
                               1               5 ms     5 ms
                               2               10 ms    10 ms
                               3               10 ms    10 ms
                               4               20 ms    10 ms
                               5               20 ms    20 ms
                               6               40 ms    20 ms
                               7               40 ms    40 ms

Notes: 1:       CCITT T.30 does not provide for answering station to specify 
                all speeds exactly using the DIS frame.  Implementation of some 
                BR codes (e.g., code 2) by an answering DCE is manufacturer 
                specific.
	*	Not supported
	**	RC144AC only


<CAN>, Escape from transmission

The DCE may request the DTE to halt phase C transmission, by sending an cancel 
<CAN> character (024) to the DTE. In this case, the DTE should terminate Phase 
C transmission, issue <CAN>, and wait for the OK response code from the DCE.


+FET=, Transmit Page Punctuation

Syntax:	+FET=<ppm>[,<pc>,<bc>,<fc>]
DCE response:
	+FPTS:<ppr>	-when receive from remote OK

This command is used to punctuate page and document transmission after one or 
more +FDT commands. This command generates T.30 Post Page Messages selected by 
the <ppm> code (Table 3-3)

The +FET=<ppm> command indicates that the current page is complete; no more 
data will be appended to it. The value indicates if there any additional pages 
are to be sent and, if so, whether there is a change in any of the document 
parameters.

The DTE can command the DCE to generate PRI-Q messages with the +FET=<ppm> 
command using ppm codes 4-6 (Table 3-3).

This command must be sent within the timeout specified by +FPHCTO after sending 
Phase C data, or else the DCE will end the page and document transmission. If 
the Phase C timeout is reached, the DCE sends an EOP post page message and 
terminates the session.

The remote facsimile station should respond to the post page message with a 
post page response. The DCE will report this using the +FPTS:<ppr> response 
(Table 3-4).


End a page

The +FEt command causes the DCE to append an ETC (6 eol) pattern as needed and 
entered Phase D by sending the selected T.30 Post Page Message.

The +FET=1 (EOM) command signals the remote station that the nest document will 
have a new DCS negotiated; this causes the session to re-enter Phase B.


+FDR, Begin or Continue Phase C Receive Data

Syntax	: +FDR <CR>
Default Value	: 2 seconds in some places

The +FDR command initiates transition to Phase C data reception. This can occur 
after answering, dialing, a document is received, or a page is received.

The DCE reports the negotiated T.30 parameters, with the remote ID information 
if available. When DCE is ready to commence data transfer, it issues a CONNECT 
response code. If the DCe cannot resume data transfer because there is no more 
data, it responds OK. When the DTE is ready to accept data, it issues an <DC2> 
character (018) to the DCE.

If the DTE issues an <XON> character to the DCE for flow control, the DCE 
signals the DTE when its buffers are empty by sending a <DLE><DC2> (<016><018>) 
character pair.

When the DCe delivers that last byte of a page, the DCE reports the Page 
Transfer Status via the +FPTS:<ppr> response (Table 3-4).

After the Page Transfer Status Report, the DCe report the post page message 
from the remote facsimile station via the +FET:<ppm> response (Table 3-3) which 
signals the intentions of the remote station.

The DCE holds the post page response message to the remote facsimile station 
(MCF, etc.), represented in the +FPTS parameter until the next +FDR command. 
The DTE may modify the +FPTS parameter before issuing the +FDR command which 
releases that message. The DTE must issue a +FDR command to release Post Page 
Message.



Table3-3 Post Page Message Codes

ppm
Code          Mnemonic                        Description

0             [PPS-]MPS                       Another page next, same
                                              document
1             [PPS-]EOM                       Another document next
2             [PPS-]EOP                       no more pages or documents
3             PPS-NULL                        Another partial page next
4             [PPS-]PRI-MPS                   Another page, procedure
                                              interrupt
5             [PPS-]PRI-EOM                   Another document, procedure
                                              interrupt

6             [PPS-]PRI-EOP                   All done, procedure interrupt
7             CTC                             Continue to correct
8 - 15        EOR-                            End-of-Retransmission (8) +
=8+ppm                                        Post Page Message (ppm
                                              code)




Table 3-4 Post Page Response Message Codes

ppr
Code          Mnemonic                        Description

0             PPR                             Partial page errors
1             MCF                             Page good
2             RTN                             Page bad; retrain request
3             RTP                             Page good; retrain request
4             PIN                             Page bad; interrupt request
5             PIP                             Page good; interrupt request


Initiate Document Reception

The +FDR command may be issued in Phase B after an answer command, or in Phase 
B after a previous document.

The DCe response in stream mode is:
	+FCFR			when CFR sent
	[+FTSI:<remote ID string>]		if new TSI received
	+FDCS:<T.30 subparameter string>]	if new DCS
	CONNECT
	(<DC2> needed from DTE here)
	<Phase C data stream>
	<DLE><ETX>
	+FPTS:<ppr>, <lc> [,<blc>, <cblc>]
	+FET:<ppm>
	OK
	( DTe must issue +FDR command to release post page response)


Continue Document Reception

The DTe may issue the +FDR command in Phase D, which releases the post page 
message, and indicates readinessto receive another page after receipt of a 
Multipage (+FET:0) or PPS-NULL (+FET:3) message.  The DCE response will be:

	CONNECT
	(<DC2> needed from DTE here)
	<Phase C data stream)
	<DLE><ETX>
	+FPTS:<ppr>, <lc> [,<blc>, <cblc>]
	+FET:<ppm>
	OK
	(DTE must issue +FDR command to release post page response)

if done receiving:
	+FHNG: <hangup cause code>
	OK

	continue page reception


Phase C Data Framing

Phase C data must be presented to the DTE in stream mode. The DCE will 
transfer the stream of data to the DTE, followed by the <DLE><ETX> stream 
termination characters. The DCE will filter the stream.


Phase C Data Format

The received data format is negotiated under T.30 reported by the
+FDCS:VR, BR, WD, LN, DF, EC, BF, ST response.

The DCE will delete the terminating RTC (6 EOLs) patterns. The DCE may strip 
zero fill bits from the data, to minimize storage needs.


<CAN>, Escape from Reception

From the +FDR command until the end of Phase D date, the DCE is a date transfer 
state, and will not respond to DTE command characters.  The DCE will respond to 
three ASCII control charcters: <DC1> (017) and <DC3> (019) flow control 
characters, and cancel <CAN> (024).

Upon receipt of the <CAN> character, the DCE will terminate the reporting of 
received data by sending trailing <DLE><ETX> characters to the DTE, and will 
then execute an implied +FK command in order to conduct an orderly 
disconnection.


+FK, Session Termination

Syntax:	+FK

The +FK command causes the DCE to terminate the session in an orderly manner. 
In particular, the DCE will send a DCN message at the next opportunity and hang 
up. At the end of the termination process, the DCe will report the +FHNG 
response with result code (Table 3-5).

This operation can be invoked using the cancel <CAN> character during the Phase 
C data reception (see prior section)

The DCe will will until the current page completes, unless the reception is of 
unlimited length; in that case, the DCE may halt reception and terminate the 
session at any time.


SERVICE CLASS 2 DCE RESPONSES

The DCE sends information responses to the DTE as a facsimile session proceeds. 
They indicate the state of the facsimile session and convey needed information. 
These messages are solicited messages generated in execution of DTE action 
commands described in SERVICE CLASS 2 ACTION COMMANDS above.

The DCE precedes and follows the following information responses with <CR><LF>.

The DCE provides the on-line status of several session parameters when they are 
available during T.30 handshaking. These include the remote ID string and the 
DIS/DCS parameters. These responses report the T.30 session parameter frames. 
The subparameters are described in Table 3-2.


+FCON, Facsimile Connection Response

+FCON indicates connection with a fax machine. It is released by detection of 
HDLC flags in the first received frame. +FCON is generated in response to an 
Originate or Answer command.



Table 3-5. Hangup Status Codes

Code                            Cause Description


0-9                             Call Placement and Termination

0                               Normal and proper end of connection
1                               Ring Detect without successful handshake
2                               Call aborted, from +FK or AN
3                               No Loop Current

10-19                           Transmit Phase A & Miscellaneous Errors

10                              Unspecified Phase A error
11                              No Answer (T.30 T1 timeout)

20-39                           Transmit Phase B Hangup Codes

20                              Unspecified Transmit Phase B error
21                              Remote cannot receive or send
22                              COMREC error in transmit Phase B
23                              COMREC invalid command received
24                              RSPEC error
25                              DCS sent three times without response
26                              DIS/DTC received 3 times; DCS not recognized
27                              Failure to train at 2400 bps or +FMINSP value
28                              RSPREC invalid response received

40-49                           Transmit Phase C Hangup Codes

40                              Unspecifies Transmit Phase C error
43                              DTE to DCE data underflow
                                                                              
50-69                           Transmit Phase D Hangup Codes

50                              Unspecified Transmit Phase D error
51                              RSPREC error
52                              No response to MPS repeated 3 times
53                              Invalid response to MPS
54                              No response to EOP repeated 3 times
55                              Invalid response to EOP
56                              No response to EOM repeated 3 times
57                              Invalid response to EOM
58                              Unable to continue after PIN or PIP

70-89                           Reveive Phase B Hangup Codes

70                              Unspecified receive Phase B error
71                              RSPREC error
72                              COMREC error
73                              T.30 T2 timeout, expected page not received
74                              T.30 T1 timeout after EOM received

90-99                           Receive Phase C Hangup Codes

90                              Unspecified receive Phase C error
91                              Missing EOL after 5 seconds
92                              Unused code
93                              DCE to DTE buffer overflow
94                              Bad CRC or frame (ECM or BFT modes)

100-119                         Receive Phase D Hangup Codes

100                             Unspecified Receive Phase D error
101                             RSPREC invalid response received
102                             COMREC invalid response received
103                             Unable to continue after PIN or PIP

120-255                         Reserved Codes



+FDCS:, Report Current Session Capabilities

Syntax	: +FDCS:VR,BR,WD,LN,DF,EC,BF,ST

+FDCS:<string> reports the negotiated parameters. Phase C data will be formated 
as described by the subparameters. This message may be generated in execution 
of +FDT or +FDR commands before the CONNECT result code if new DCS frames are 
generated or received. (see Table 3-2)


+FDIS:, Report Remote Station Capabilities

Syntax	: +FDIS:VR,BR,WD,LN,DF,EC,BF,ST

+FDIS:<string> reports remote facsimile station capabilities and intentions. 
The parameters are provided in ASCII notation (See Table 3-2).

This message is generated in execution of Originate, Answer, +FDT, or +FDr 
commands.


+FCFR, Indicate Confirmation to Receive

Syntax	: +FCFR

The DCe sends a  +FCFR response to the DTE upon reception of an accepted TCF 
training burst and a valid DCS signal from the remote machine. This indicates 
that the DCE will receive Phase C data after the remote station receives the 
local DCE's CFR message. The FCFR message is generated in execution of a +FDR 
command.


+FTSI:, Report the Transmit Station ID

Syntax	: +FTSI: "<TSI ID string>" Transmit Station ID

This response reports the received transmit station ID string, if any, This 
message is generated in execution of Originate, Answer, +FDT, or +FDR commands.


+FCSI:, Report the Called Station ID

Syntax	: +FCSI: "<CSI ID string>" Called Station ID

This response reprots the received called station ID string, if any. This 
message is generated in execution of Originate, Answer, +FDT, or +FDR commands.


+FPTS:, Receive Page Tranfer Status

Syntax	: +FPTS:<ppr>, <lc> [,<blc>, <cblc>

The +FPTS:<ppr> is generated by the DCe at the end of Phase C data reception in 
execution of a +FDR command.

The <ppr> is generated by the DCE; it depends on the DCE capabilities at T.4 
error checking. See Table 3-4 for <ppr> values.

The receiving DCE will count the lines and may optionally generate bad line 
counts. These values are;

	<lc>	= line count
	<blc>	= bad line count
	<cblc>	= consecutive bad line count

A receiving DTE may inspect <ppr> and write a modified value into the +FPTS 
parameter. The DCE will hold the corresponding Post Page Response message until 
released by a +FDR command from the DTE.


+FET:, Post Page Message Response

Syntax:	+FET:<ppm>

The +FET:<post page message> respone is generated by the receiving DCE after 
the end of Phase C reception on receipt of the post-page message from the 
transmitting station. The +FET:<ppm> response is generated in execution of a 
+FDR command. The <ppm> codes respond to the T.30 post page message (Table 3-3)


+FPTS:, Transmit Page Tranfer Status

Syntax	: +FPTS:<ppr>

The +FPTS: response reports a <ppr> number representing the copy quality and 
related post-page message responses received from the remote DCE. The set of 
valid <ppr> values are defined in Table 3-4.

The +FPTS:<ppr> response is generated in execution of a +FET=<ppm> command.


+FHNG:, Call Termination with Status

Syntax	: +FHNG: <hangup status code>

+FHNG indicates that the call has been terminated. The hangup cause is reported 
and stored in the +FAXERR parameter for later inspection.  The <hangup status 
code> values are decscribed in Table 3-5.

+FHNG:<hsc> is a possible intermediate recult code to any DTE action command 
described in SERVICE CLASS 2 ACTION COMMANDS. It is always followed by the OK 
final result code.

Upon termination of a call, the DCe determines the cause of termination and 
reports it as part of the FHNG:<hsc> response. It also stores this <hsc> code 
in the +FAXERR parameter for later inspection.


SERVICE CLASS 2 PARAMETERS

All the Service Class 2 parameters can be read, written, and tested for range 
of legal values by the DCE. The general syntax is described in COMMAND SYNTAX 
AND GUIDELINES.

Group 3 FAX devices negotiate session parameters in DIS, DCS, and DTC frames. 
The following parameters are provided to condition the facsimile DCE for the 
capabilities it will offer and to report the session settings negotiated.

The three primary T.30 session parameters are +FDCC, +FDIS and +FDCS. They are 
compound parameters, using values listed in Table 3-2.


+FDCC, DCE Capabilities Parameters

Write Syntax	: +FDCC=VR, BR, WD, LN, DF, ED, BF, ST
Valid Values	: See Table 3-2
Default values	: 0,3,0,3,0,0,0,0

+FDCC allows the DTE to sense and constrain the capabilities of the facsimile 
DCE from the choices defined in CCITT T.30. When +FDCC is modified by the DTE, 
the DCE copies +FDCC into +FDIS.


+FDIS, Current Sessions Capabilities Parameters

Write Syntax	: +FDIS=VR, BR, WD, LN, DF, ED, BF, ST
Valid values	: See Table 3-2
Default values	: 0,3,0,3,0,0,0,0

The +FDIS parameter allows the DTE to sense and constrain the capabilities used 
for the current session. The DCE uses +FDIS to generate DIS or DTC messages 
directly, and uses +FDIS and received DIS messages to generate DCS messages.

The DCe initializes the +FDIS parameter from the +FDCC parameter on 
initialization, when +FDCC is written, and at the end of the session.


+FPTS:, Receive Page Transfer Status

Syntax	: +FPTS:<ppr>, <lc> [,<blc>, <cblc>]

The +FPTS:<ppr> is generated by the  DCE at the end of Phase C data reception 
in execution of a +FDR command.

The <ppr> is generated by the DCE; it depends on the DCE capabilities at T.4 
error checking. See Table 3-4 for <ppr> values.

The receiving DCE will count the lines and may optionally generate bad line 
counts. These values are;
	<lc>	line count
	<blc>	bad line count
	<cblc>	consecutive bad line count

A receiving DTE may inspect <ppr> and write a modified value into the +FPTS 
parameter. The DCe will hold the corresponding Post Page Response message until 
released by a +FDR command from the DTE.


+FET:, Post Page Message Response

Syntax	: +FET<ppm>

The +FET:<post page message> response is generated by a receiving DCE after the 
end of Phase C reception on receipt of the post-page message from the 
transmitting station. The +FET:<ppm> response is generated in execution of a 
+FDR command. The <ppm> codes respond to the T.30 post page message (Table 
3-3).


+FPTS:, Transmit Page Transfer Status

Syntax	: +FPTS:<ppr>

The +FPTS: response reports a <ppr> number representing a copy quality and 
related post-page message responses received from the remote DCE. The set of 
valid <ppr> values are defined in Table 3-4.

The +FPTS:<ppr> response is generated in execution of a +FET=<ppm> command.


+FHNG:, Call Termination with Status

Syntax	: ++FHNG:<hangup status code>

+FHNG indeicates that the call bas been terminated. The hangup cause is 
reported and stored in the +FAXERR parameter for later inspection.  The <hangup 
status code> values are described in Table 3-5.

+FHNG:<hsc> is a possible intermediate result code to any DTE action command 
described in SERVICE CLASS 2 ACTION COMMANDS. It is always followed by the OK 
final result code.

Upon termination of a call, the DCE determines the cause of termination and 
reports it as part of the FHNG:<hsc> response. It also stores this <hsc> code 
in the +FAXERR parameter for later inspection.

The hangup values are organized according to the phases of the facsimile 
transaction as defined by T.30.


+FLID=, Local ID String

Write Syntax	: +FLID="<local ID string>"
Valid values	: 20 characters ASCII string
Default value	: empty

If FLID is not a null string, it generates a TSI or CSI frame.

If the DCe supports use of Table 3/T.30 only, the response to a +FLID=? command 
is "(20 (32, 43, 48-57)". If the DCe support printable ASCII <, the response 
is: "(20) (32-127) <CRLF>." The first "(20" represents string length: the 
seconds (character values) field reports supported string values.

Notes	: 1. The string is saved in RAM
	  2. Non-numeric characters are not filtered out.


+FCR, Capability to Receive

Write Syntax	: +FCR=<value>
Valid values	: 1, 0
Default value	: 0

+FCR=0 indicates that the DCE will not receive message data. This can be used 
when the DTE has insufficient storage. The can send and can be polled for a 
file.

+FCR is sampled in CCITT T.30 Phase A and Phase D.


+FPTS=, Page Transfer Status

Write Syntax	: +FPTS=<ppr>
Valid values	: 1, 2, 3, 4, 5
Default value	: 0

The +FPTS parameter contain a value representing the post page response, 
including copy quality and related end-of-page status.  These values correspond 
topost page response messages defined in T.30. The receiving DCe sets this 
parameter after it receives a page of Phase C data. The transmitting DCE sets 
this parameter with the status reported by the receiving station. The DTE may 
inspect or modify this parameter.

The set of <ppr> values are defined in Table 3-4. These values are also 
reported in the +FPTS response to the +FDR command.


+FCQ, Copy Quality Checking

Write Syntax	: +FCQ=<value>
Valid values	: 0
Default value	: 0

This parameter controls the Copy Quality checking by a receiving facsimile DCE.

The DCe returns +FXQ=0 which indicates the DCE does no quality checking. The 
DCe will generate Copy Quality OK (MCF) responses to complete pages, and set 
+FPTS=1.


+FPHCTO, DTE Phase C Response Time-out

Write Syntax	: +FPHCTO=<value>
Valid values	: 0 - 255, 100 millisecond units.
Default values	: 30

The +FPHCTO command determines how long the DCE will wait for a command after 
reaching the end of data when transmitting in Phase C.  When this time-out is 
reached, the DCe assumes there are no more pages and no documents to send. It 
then sends the T.30 EOP response to the remote device.


+FAXERR, T.30 Session Error Report

Read Syntax	: +FAXERR, T.30 Session Error Report
Valid values	: 0 - 255, see Table 3-5 for meaning

This read-only parameter indicates the cause of the hangup. Table 3-5 shows the 
valid values for this parameter as well as the meaning of the each value. 
+FAXERR is set be the DCE at the conclusion of a fax session. The DCE resets 
+FAXERR to 0 at the beginning of Phase A off-hook time.


+FBOR, Data Bit Order

Write Syntax	: +FBOR=<value>
Valid values	: 0, 1
Default value	: 0

This parameter controls the mapping between PSTN facsimile data and
DTE-DCE link. There are two choices:
        Direct          : The first bit transferred of each byte on
                          the DTE-DCE link is the first bit
                          transferred on the PSTN data carrier.
        Reversed        : The last bit transferred of each byte on
                          the DTE-DCE link is the first link
                          transferred on the PSTN data carrier.

There are two data type to control:

This command controls Phase C data (T.4 encoded data) transferred during 
execution of +FDT or +FDR commands.

The following two codes are supported:
	+FBOR=0	selects direct bit order for Phase C data.
	+FBOR=1	selects reversed bit prder for Phase C data.

Note that this parameter does not affect the bit order of control characters 
generated by the DCE.


+FAA, Answer Parameter

Write Syntax	: +FAA=<value>
Valid values	: 0, 1
Default value	: 0

	+FAA=0		constrains the DCE to answer as set by +FCLASS.
        +FAA=1          indicates that the DCE can answer and
                        automatically determine whether to answer as
                        Class 2 facssimile DCE or as a data modem. If
                        the DCE automatically switches, it modifies
                        FCLAA appropriately.

Class 2 adaptive answer is implemented as follows:

First, a data mode handshake is attempted. If the DCe has been configured for 
automode detection (using the ATN1 command), the DCE may try several protocols 
before terminating attempts to make a data mode connection. This can take as 
long as 6-8 seconds.

If the data mode connection attempt fails, a facsimile Class 2 connection is 
assumed. When a connection is made as a result ot the adaptive answer, the DCE 
issues the DATA or FAX result code before the CONNECT or +FCON message to 
inform the DTE of the connection type. After making a Class 2 connection, the 
DCE stays on-line rather than going into the command mode as with a Class 1 
connection.


+FBUF?, Buffer Size

Read Syntax	: +FBUF?
DCE response syntax	: <bs>, <xoft>, <xont>, <bc>
where:
	<bs>	total buffer size
	<xoft>	XOFF threshold
	<xont>	XON threshold
	<bc>	current buffer byte count

The +FBUF parameter allows the DTE to determine the characteristics of the 
DCE's data buffer. Data buffers are used for flow control. Use of the reported 
values allow to DTE to transfer data without provoking XOFF.
