Table 4-1. Fax Class 1 and Fax Class 1.0 Commands
Command/Parameter Function Applicable in
Fax Class 1
Applicable in
Fax Class 1.0
+FCLASS=<class> Select, read or test service class X X
+FAA=<value> Auto answer enable - X
+FAE=<value> Auto answer enable X X
+FTS=<time> Stop transmission and pause X X
+FRS=<time> Wait for silence X X
+FTM=<mod> Transmit data with <mod> carrier X X
+FRM=<mod> Receive data with <mod> carrier X X
+FTH=<mod> Transmit HDLC data with <mod> carrier X X
+FRH=<mod> Receive HDLC data with <mod> carrier X X
+FAR=<off/on> Adaptive reception control - X
+FCL=<time> Carrier loss timeout - X
+FDD=<value> Double escape character replacement control - X
+FIT=<time>, <action> DTE inactivity timeout - X
+FPR=<rate> Fixed DTE Rate - X
+FMI? Report manufacturer ID - X
+FMM? Report model ID - X
+FMR? Report revision ID - X
+FLO Flow Control - X
&K Local DTE-modem flow control (see Section 3.2.3) X X
A Answer (see Section 3.2.3) X X
D <string> Dial (see Section 3.2.3) X X
H Hangup (see Section 3.2.3) X X
X = Applicable; - = Not applicable.

TABLE  I.1/T.31
DTE commands DCE responses Local DCE action Remote station action Notes
AT+FCLASS  =  1.0 OK Set Class1
ATD <string>
 Dial and send CNG
Look for Rec. V.21
Detecte flags
 Answers
Sends CED, Rec. V.21
Sends HDLC flags
 AT+FRH  =  3
implied by dialing with
+FCLASS  =  1.0
 CONNECT
<NSF frame>
<DLE> <ETX>
Sends NSF
Frame
OK
AT+FRH  =  3
 CONNECT
 Detect flags
get CSI
get FCS
accept FCS
<CSI frame data>
<DLE> <ETX>
 send CSI frame
OK
check FCS frame status OK
AT+FRH  =  3
 CONNECT
 Detect flags
get DIS
get FCS
accept FCS
 DTE must detect final
frame bit to anticipate
loss-of-carrier
<DIS frame data>
<DLE> <ETX>
 Send DIS frame
OK
send FCS
AT+FRH  =  3 NO CARRIER detect loss-of-carrier drop carrier
AT+FTH  =  3
 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
 Final frame bit clear
tells the DCE to expect
another frame.
Final frame bit set tells
the DCE not to expect
another frame
 CONNECT
<TSI frame data>
<DLE> <ETX>
CONNECT
get DCS frame
<DCS frame data>
<DLE> <ETX>
OK
AT+FTS  =  8;
 wait 80 msec
send V.29 carrier
+FTM  =  96
 CONNECT
 detect carrier
<TCF data pattern>
<DLE> <ETX>
send TCF data
drop carrier
get TCF data
OK
20 Recommendation T.31     (08/95)这几天真是够衰的，老是在传输数据过程中收到 OK？！