Multi-Tech Systems Modem Module MT3334SMI - Manual (Page 42)

ModemModule Developer’s Guide
MT3334SMI 42
Introduction
This chapter provides fax software developers with specific Class 2 fax command protocol
information to be used in development with Lucent L33xVCS modem chip set. It is assumed that
users have an understanding of ITU-TSS T.30 and T.4 concepts. The “fax command protocol” is
defined here as the set of AT Commands used to control the sending/receiving of faxes. The term
“fax” is defined as a specialized file transfer protocol for transferring black and white bit mapped
images.
AT commands are used to control parameters for this file transfer and to initiate a particular action in
the fax protocol. They also provide responses to indicate the progress and status of the transfer.
Class 2 Fax Command Implementation
The MultiModems implement an extension to the AT Command set for controlling fax transmission
and reception, which is in compliance with EIA proposed standard TIA-592 (August, 1990) as
specified by EIA subcommittee TR29.2. It involves a set of new commands, responses and
procedures.
Class 2 Fax Commands (EIA SP-2388 August 1990)
The Lucent L56xVCS Chip Set supports fax Class 2 (August ‘90) commands. These commands and
short descriptions of the commands are provided below. For more detailed information, refer to the
August 1990 proposal.
Note: The EIA SP-2388 August 1990 proposal is being updated and will be made available when
completed.
+FAA FAX Auto Answer Enable
Command Syntax: +FAA=<value>
0: Answer as FAX modem of type specified by +FCLASS
2: Automatically determine whether to answer as FAX or data modem
+FAXERR T.30 Session Error Report
Command syntax: +FAXERR
Response syntax: +FAXERR=<value>
0 - 9 Call placement and termination
0: Normal and proper end of connection
1: Ring detected without successful handshake
2: Call aborted, from +FK or <CAN>
10 - 19 Transmit phase A and miscellaneous errors
20 - 39 Transmit phase B hang-up codes
20: Unspecified transmit phase B error
23: COMREC invalid command received
25: DCS sent 3 times without response
27: Failure to train
40 - 49 Transmit phase C hang-up codes
40: Unspecified transmit phase C error