Specifications
    Chapter 2 – Fax Class1 Commands 
Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306B)  75 
Table 2-5. Fax Class 1 Answering Sequence (Receiving a Single Page) 
DTE Commands  Modem Responses  Local Modem Action  Remote Station Action  Notes 
AT+FCLASS=1  OK  Set Class 1 
  RING<-  detect ringing  dials [,send CNG] 
ATA 
<CSI frame data> 
<DLE><ETX> 
<DIS frame data> 
<DLE><ETX> 
CONNECT 
CONNECT 
OK 
off-hook, 
send CED, 
send V.21 carrier 
send flags 
send CSI frame 
send FCS 
send flags 
send DIS data 
send FCS and flags 
drop carrier 
get CED, 
detect carrier 
detect flags 
receive CSI 
get FCS 
get flags 
get DIS 
get flags 
AT+FRH=3 
implied by answering 
with +FCLASS=1.0. 
not final frame 
final frame 
AT+FRH=3 
CONNECT 
<TSI frame data> 
<DLE><ETX> 
OK 
detect carrier 
detect flags 
receive TSI 
receive FCS 
accept FCS 
send V.21 carrier 
send flags 
send TSI frame 
send FCS 
frame OK 
AT+FRH=3 
CONNECT 
<DCS frame data> 
<DLE><ETX> 
OK 
receive DCS 
receive FCS 
accept FCS 
send DCS frame 
send FCS 
final frame bit set 
frame OK 
AT+FRH=3  NO CARRIER  detect loss-of-carrier  drop carrier  DTE did not check final 
frame bit and issued 
+FRH=3
AT+FTM=96 
CONNECT 
<TCF data> 
<DLE><ETX> 
OK 
detect carrier 
receive TCF 
detect loss-of-carrier 
wait 75 ms 
send V.29 carrier 
send TCF data 
drop carrier 
AT+FRH=3 
<CFR frame data> 
<DLE><ETX> 
CONNECT 
OK 
send V.21 carrier 
send flags 
get CRF frame 
send FCS 
drop carrier 
detect carrier 
detect flags 
receive CFR 
final frame 
AT+FTM=96 
CONNECT 
<page image data> 
<DLE><ETX> 
NO CARRIER 
detect carrier 
receive page 
detect loss-of-carrier 
send V.29 carrier 
send page data 
drop carrier 
CONNECT 
<EOP frame data> 
<DLE><ETX> 
NO CARRIER 
detect carrier 
detect flags 
receive EOP 
receive FCS 
accept FCS 
wait 75 ms 
send V.21 carrier 
send flags 
send EOP frame 
send FCS 
frame OK 
AT+FRH=3  NO CARRIER  detect loss-of-carrier  drop carrier   
AT+FRH=3 
<MCFame data> 
<DLE><ETX> 
CONNECT 
OK 
send V.21 carrier 
send flags 
get MCF frame 
send FCS 
accept FCS 
detect carrier 
detect flags 
receive MCF frame 
final frame 
AT+FRH=3 
CONNECT 
<DCN frame data> 
<DLE><ETX> 
OK 
detect carrier 
detect flags 
receive DCN 
receive FCS 
accept FCS 
send V.21 carrier 
send flags 
send DCN frame 
send FCS 
frame OK 
AT+FRH=3  NO CARRIER  detect loss-of-carrier  drop carrier  end of session 
ATH0 OK  hang up     










