Multi-Tech Systems Modem Module MT3334SMI - Manual (Page 32)

ModemModule Developer’s Guide
MT3334SMI 32
Introduction
The Service Class 1 standard (EIA/TIA-578) defines the commands that a PC user may issue to
configure and control a fax/data modem, and the responses (result codes) that the fax/data modem
may issue in response to those commands.
The Class 1 standard provides the basic services needed to support Group 3 fax operation. Support
of the 1988 CCITT (ITU-T) T.30 recommended procedures for session management and the T.4
recommendation for image data handling are required at the PC.
Service Class 1 provides the following services (as required, or optional in Group 3 facsimile
operation):
• Connection (originate and answer),
• Waiting and silence detection,
• Data transmission and reception (data transfer),
• HDLC (High-level Data Link Control) data framing/transparency/error detection, and
• Message generation/response.
HDLC is an ISO standard, bit-oriented data communications protocol. HDLC control information is
consistently placed, and specific control bit patterns are considerably different than those used as
data, providing a largely error-free protocol.
Class 1 Fax Command Summary
The ModemModule Fax Class 1 enhancements are implemented with six AT+F (for Fax) commands.
The +FTM, +FRM, +FTH, and +FRH commands must be entered as the last command in the
command string (i.e., the last command on the command line). The +FTS and the +FRS commands
can be entered anywhere in the command string.
Command Description
+FCLASS? Display Current Class
+FCLASS=? Display Service Class Capabilities
+FCLASS=<> Select Service Class
+FTS= Stop tranmission and pause (10 ms intervals, 0-255)
+FTS=? Display the valid +FTS= range (0-255)
+FRS= Wait for silence (10 ms intervals, 0-255)
+FRS=? Display the valid +FRS= range
+FTM= Transmit data with specified carrier
+FTM=? Display the valid +FTM= carrier range
+FRM= Receive data with specified carrier
+FRM=? Display the valid +FRM= carrier range
+FTH= Transmit HDLC data with specified carrier
+FTH=? Display the valid +FTH= carrier range
+FRH= Receive HDLC data with specified carrier
+FRH=? Display the valid +FRH= carrier range
If entering multiple commands on the command line, use semicolons between commands. These +F
commands are defined in the following sections. The parameter may take on the following
values.