Specifications

Chapter 2 – Fax Class1 Commands
Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306B) 74
Examples
Examples of calling (transmitting) and answering (receiving) one page using Fax Class 1 commands are shown in
Table 2-4 and Table 2-5, respectively. The examples show the interchange between the DTE and the modem for
various cases. Comments are included to explain how to handle various situations. Commands and responses are in
upper case and comments are in lower case. All streams of data denoted by <..frame> are terminated by the
<DLE><ETX> characters.
Table 2-4. Fax Class 1 Calling Sequence (Transmitting a Single Page)
DTE Commands Modem Responses Local Modem Action Remote Station Action Notes
AT+FCLASS=1 OK Set Class 1
ATDT<string>
CONNECT
<NSF frame>
<DLE><ETX>
OK
Dial and send CNG
Look for V.21
Detect flags
Answer
send CED, V.21
Send HDLC flags
Send NSF frame
AT+FRH=3
implied by dialing with
+FCLASS=1.0
AT+FRH=3
CONNECT
<CFI frame data>
<DLE><ETX>
OK
Detect flags
get CSI
get FCS
accept FCS
send CSI frame
check FCS
Frame status OK
AT+FRH=3
CONNECT
<DIS frame data>
<DLE><ETX>
OK
Detect flags
get DIS
get FCS
accept FCS
send DIS frame
check FCS
DTE must detect final
frame bit to anticipate
loss of carrier
AT+FRH=3 NO CARRIER detect loss-of-carrier drop carrier
AT+FRH=3
<TSI frame data>
<DLE><ETX>
<DCS frame data>
<DLE><ETX>
CONNECT
CONNECT
OK
send V.21 carrier
send flags
send TSI frame
send FCS
send flags
send DCS frame
send FCS, flags
drop carrier
detect carrier
detect flags
get TSI frame
get DCS frame
Final frame bit clear tells
the modem to expect
another frame.
Final frame bit set tells
the modem not to
expect another frame
AT+FTS=8;
+FTM=96
<TCF data pattern>
<DLE><ETX>
CONNECT
OK
wait 80 ms
send V.29 carrier
send TCF data
drop carrier
detect carrier
get TCF data
AT+FRH=3
CONNECT
<CFR frame data>
<DLE><ETX>
OK
detect carrier
detect flags
get CFR frame
check FCS
accept FCS
send V.21 carrier
send flags
get CRF frame
send FCS
Final frame bit set.
frame OK
AT+FRH=3 NO CARRIER detect loss-of-carrier drop carrier
AT+FTM=96
<page image data>
<DLE><ETX>
CONNECT
OK
send V.29 carrier
send page data
drop carrier
detect carrier
receive page
AT+FTS=8;
+FRH=3
<EOP frame data>
<DLE><ETX>
CONNECT
OK
wait 80 ms
send V.21 carrier
send flags
send EOP frame
send FCS
drop carrier
detect carrier
detect flags
receives EOP
final frame
AT+FRH=3
CONNECT
<MCF frame data>
<DLE><ETX>
OK
detect carrier
detect flags
get MCF frame
check FCS
accept FCS
send V.21 carrier
send flags
get MCF frame
send FCS
Final frame bit set.
frame OK
AT+FRH=3 NO CARRIER detect loss-of-carrier drop carrier
AT+FRH=3
<DNC frame>
<DLE><ETX>
CONNECT
OK
send V.21 carrier
send flags
send DNC frame
send FCS
drop carrier
detect carrier
detect flags
receive DC|NC
final frame
ATH0 OK hang up hang up