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？！

今天上网转悠，最近精神不是很好，儿子每天早上四点就起来了，我也只好五点多起床，同时由于到了30岁，人无远虑，必有近忧。编程编了八年，有点七年之痒的意思了。

看到 『天涯杂谈』中国移动通信vs多普达818 http://www.tianyaclub.com/new/publicforum/content.asp?idwriter=0&key=0&stritem=free&idarticle=313206&flag=1 当打开网页时，电话提示无法接通的问题。

觉得有点意思，以前用MC35西门子上网GPRS的时候，如果正在进行SOCKET连接并传输数据，

如果在下载过程中，http://www.yippeesoft.com数据正在传输，那么此时电话呼入，较长时间没有响应，最后提示：该号码暂时无法拨通。

如果此时暂停下载，停止数据传输，那么呼入电话正常，拨打方听到正常的铃音

，正好和这个类似。上网找了一些资料，也看不出什么门道。

GPRS的Class有两类，即按服务种类划分的Class，以及按GPRS时隙的分配传输类型来划分的Class。
　　一、GPRS的服务类型
　　按所提供的服务种类来说，现在有Class A、B、C三种。
　　Class A可以在上网的同时接听电话，其技术含义是同时支持包交换（数据）和电路交换（语音）。
　　Class B可以上网和接电话，但不能同时进行，其技术含义是虽然也支持包交换和电路交换，但不可在同一时刻支持包交换和电路交换，状态可以切换；
　　Class C则只能上网，什么时候都不能打电话，其技术含义是它只支持包交换。
　　到目前为止，我所知道的手机只有Class B类型，也就是说，它既可以GPRS上网，也能打电话，但不能同时进行。
　　不过我的推论是，GPRS的服务类型Class并不完全由手机决定，而是需要GPRS网络运营商提供相应服务才能进行。两者是互相配合和依存的关系。

　　二、GPRS的传输类型
　　GPRS是对GSM网络的扩展，它对GSM网络的地面网部分进行了改造，保留了无线部分的大部分设施，并配合软件的升级，使之能够支持数据传输。
　　GPRS网为每个用户分配最多8个时隙（时间片）来传输数据，这8个时隙又分下行和上行，所以它们的组合数就多了。具体的组合情况，现在都用Class的传输类型来描述。按照“Class类型、下行数，上行数、简称”的顺序，我们有如下几个常用的Class类型：
　　Class2 2, 1, 2+1 　　Class4 3, 1, 3+1  　　Class8 4, 1, 4+1    　　Class10 4, 2, 4+2 http://sms1.2liang.com/files/436.htm

MC35是西门子移动通讯出品的第一款GPRS模块，MC35向上兼容全部TC35功能，此外还集成了高速GPRS技术。可将GPRS技术广泛集成于移动电脑、PDA、智能电话以及其它设备之中。具备持久的在线连接、快速数据接入、高速数据传输速率等特点。
模块具体参数如下：
支持EGSM900/GSM1800双频
支持GRPS Class 8/Class B
支持GSM phase2/2+
输出功率：EGSM900时，2W / GSM1800，1W
输入电压：3.3-4.8V
功耗：休眠状态，3.0mA ；空闲状态，10.0mA；发射状态，300mA （平均），2.0A（峰值）
控制：AT指令直接控制
重量：16g
体积：54.5*36*6.65mm
环境温度：-25°C / +55°C
数据速率：CSD状态下最大速率14.4kbps，GPRS状态下行最大速率85.6kbps
接口：40pin
包括电源、3V SIM卡、RS232接口、语音、控制等管脚 / 50Ω天线接口

这是MC35的参数，也就是说，采用的CLASSB，

gprs网络编程和电话呼入的冲突  http://www.yippeesoft.com/blog/p/GPRSSOCKCALLIN.php

IN : OK
OUT: AT+FCR=1
IN : AT+FCR=1
IN : OK
OUT: AT+FLID="23"
IN : AT+FLID="23"
IN : OK
OUT: AT+FBOR=0
IN : AT+FBOR=0
IN : OK
OUT: AT+FDIS=?
IN : AT+FDIS=?
IN : (0,1),(0-5),(0-2),(0-2),0,0,0,(0-7)
IN : OK
OUT: AT+FDIS=1,3
IN : AT+FDIS=1,3
IN : OK
OUT: AT+FCLASS?
IN : AT+FCLASS?
IN : 2
IN : OK
OUT: AT
IN : AT
IN : OK
OUT: ATH0
IN : ATH0
IN : OK
OUT: AT
IN : AT
IN : OK
OUT: ATZ
IN : ATZ
IN : OK
OUT: AT&F
IN : AT&F
IN : OK
OUT: ATV1
IN : ATV1
IN : OK
OUT: ATL0M1
IN : ATL0M1
IN : OK
OUT: ATS0=0
IN : ATS0=0
IN : OK
OUT: AT+FCLASS=?
IN : AT+FCLASS=?
IN : 0,1,1.0,2,8,10
IN : OK
OUT: AT+FCLASS=2
IN : AT+FCLASS=2
IN : OK
OUT: AT+FCR=1
IN : AT+FCR=1
IN : OK
OUT: AT+FLID="23"
IN : AT+FLID="23"
IN : OK
OUT: AT+FBOR=0
IN : AT+FBOR=0
IN : OK
OUT: AT+FDIS=?
IN : AT+FDIS=?
IN : (0,1),(0-5),(0-2),(0-2),0,0,0,(0-7)
IN : OK
OUT: AT+FDIS=1,3
IN : AT+FDIS=1,3
IN : OK
OUT: AT+FCLASS?
IN : AT+FCLASS?
IN : 2
IN : OK
OUT: AT
IN : AT
IN : OK
IN : RING
OUT: ATA
IN : ATA
IN : +FCON
IN : +FTSI: "Fax                 "
IN : +FDCS: 1,3,0,0,0,0,0,0
IN : OK
OUT: AT+FDR
IN : AT+FDR
IN : +FCFR
IN : +FDCS: 1,3,0,0,0,0,0,0
IN : CONNECT
IN : +FPTS: 1,2394,0,0
IN : +FET: 0
IN : OK
OUT: AT+FDR
IN : AT+FDR
IN : CONNECT
IN : +FPTS: 1,2394,0,0
IN : +FET: 2
IN : OK
OUT: AT+FDR
IN : AT+FDR
IN : +FHNG: 0
IN : OK
OUT: ATH0
IN : ATH0
IN : OK
OUT: ATH0
IN : ATH0
IN : OK
OUT: AT
IN : AT
IN : OK
OUT: ATZ
IN : ATZ
IN : OK
OUT: AT&F
IN : AT&F
IN : OK
OUT: ATV1
IN : ATV1
IN : OK
OUT: ATL0M1
IN : ATL0M1
IN : OK
OUT: ATS0=0
IN : ATS0=0
IN : OK
OUT: AT+FCLASS=?
IN : AT+FCLASS=?
IN : 0,1,1.0,2,8,10
IN : OK
OUT: AT+FCLASS=2
IN : AT+FCLASS=2
IN : OK
OUT: AT+FCR=1
IN : AT+FCR=1
IN : OK
OUT: AT+FLID="23"
IN : AT+FLID="23"
IN : OK
OUT: AT+FBOR=0
IN : AT+FBOR=0
IN : OK
OUT: AT+FDIS=?
IN : AT+FDIS=?
IN : (0,1),(0-5),(0-2),(0-2),0,0,0,(0-7)
IN : OK
OUT: AT+FDIS=1,3
IN : AT+FDIS=1,3
IN : OK
OUT: AT+FCLASS?
IN : AT+FCLASS?
IN : 2
IN : OK
OUT: AT
IN : AT
IN : OK
OUT: ATH0
IN : ATH0
IN : OK
OUT: AT
IN : AT
IN : OK
OUT: ATZ
IN : ATZ
IN : OK
OUT: AT&F
IN : AT&F
IN : OK
OUT: ATV1
IN : ATV1
IN : OK
OUT: ATL0M1
IN : ATL0M1
IN : OK
OUT: ATS0=0
IN : ATS0=0
IN : OK
OUT: AT+FCLASS=?
IN : AT+FCLASS=?
IN : 0,1,1.0,2,8,10
IN : OK
OUT: AT+FCLASS=2
IN : AT+FCLASS=2
IN : OK
OUT: AT+FCR=1
IN : AT+FCR=1
IN : OK
OUT: AT+FLID="23"
IN : AT+FLID="23"
IN : OK
OUT: AT+FBOR=0
IN : AT+FBOR=0
IN : OK
OUT: AT+FDIS=?
IN : AT+FDIS=?
IN : (0,1),(0-5),(0-2),(0-2),0,0,0,(0-7)
IN : OK
OUT: AT+FDIS=1,3
IN : AT+FDIS=1,3
IN : OK
OUT: AT+FCLASS?
IN : AT+FCLASS?
IN : 2
IN : OK
OUT: AT
IN : AT
IN : OK

启动
正在初始化传真 Modem…
OUT: AT
IN : AT
IN : OK
OUT: ATZ
IN : ATZ
IN : OK
OUT: AT&F
IN : AT&F
IN : OK
OUT: ATV1
IN : ATV1
IN : OK
OUT: AT
IN : AT
IN : OK
OUT: AT+FAA=2
IN : AT+FAA=2
IN : ERROR
OUT: AT+FAA=0
IN : AT+FAA=0
IN : OK
OUT: ATH0
IN : ATH0
IN : OK
OUT: AT
IN : AT
IN : OK
OUT: ATZ
IN : ATZ
IN : OK
OUT: AT&F
IN : AT&F
IN : OK
OUT: ATV1
IN : ATV1
IN : OK
OUT: ATL0M1
IN : ATL0M1
IN : OK
OUT: ATS0=0
IN : ATS0=0
IN : OK
OUT: AT+FCLASS=?
IN : AT+FCLASS=?
IN : 0,1,1.0,2,8,10
IN : OK
OUT: AT+FCLASS=2
IN : AT+FCLASS=2
IN : OK
OUT: AT+FCR=1
IN : AT+FCR=1
IN : OK
OUT: AT+FLID="23"
IN : AT+FLID="23"
IN : OK
OUT: AT+FBOR=0
IN : AT+FBOR=0
IN : OK
OUT: AT+FDIS=?
IN : AT+FDIS=?
IN : (0,1),(0-5),(0-2),(0-2),0,0,0,(0-7)
IN : OK
OUT: AT+FDIS=1,3
IN : AT+FDIS=1,3
IN : OK
OUT: AT+FCLASS?
IN : AT+FCLASS?
IN : 2
IN : OK
OUT: AT
IN : AT
IN : OK
OUT: AT+FDCC=1
IN : AT+FDCC=1
IN : OK
OUT: ATDT8569
IN : ATDT8569
IN : +FCON
IN : +FDIS: 1,5,0,2,1,0,0,0
IN : OK
OUT: AT+FDT
IN : AT+FDT
IN : +FDCS: 1,5,0,2,0,0,0,0
IN : CONNECT
OUT: 
IN : 

IN : OK
OUT: AT+FET=2
IN : AT+FET=2
IN : +FPTS: 1
IN : +FHNG: 0
IN : OK
OUT: ATH0
IN : ATH0
IN : OK
OUT: ATH0
IN : ATH0
IN : OK
OUT: AT
IN : AT
IN : OK
OUT: ATZ
IN : ATZ
IN : OK
OUT: AT&F
IN : AT&F
IN : OK
OUT: ATV1
IN : ATV1
IN : OK
OUT: ATL0M1
IN : ATL0M1
IN : OK
OUT: ATS0=0
IN : ATS0=0
IN : OK
OUT: AT+FCLASS=?
IN : AT+FCLASS=?
IN : 0,1,1.0,2,8,10
IN : OK
OUT: AT+FCLASS=2
IN : AT+FCLASS=2
IN : OK
OUT: AT+FCR=1
IN : AT+FCR=1
IN : OK
OUT: AT+FLID="23"
IN : AT+FLID="23"
IN : OK
OUT: AT+FBOR=0
IN : AT+FBOR=0
IN : OK
OUT: AT+FDIS=?
IN : AT+FDIS=?
IN : (0,1),(0-5),(0-2),(0-2),0,0,0,(0-7)
IN : OK
OUT: AT+FDIS=1,3
IN : AT+FDIS=1,3
IN : OK
OUT: AT+FCLASS?
IN : AT+FCLASS?
IN : 2
IN : OK
OUT: AT
IN : AT
IN : OK
OUT: ATH0
IN : ATH0
IN : OK
OUT: AT
IN : AT
IN : OK
OUT: ATZ
IN : ATZ
IN : OK
OUT: AT&F
IN : AT&F
IN : OK
OUT: ATV1
IN : ATV1
IN : OK
OUT: ATL0M1
IN : ATL0M1
IN : OK
OUT: ATS0=0
IN : ATS0=0
IN : OK
OUT: AT+FCLASS=?
IN : AT+FCLASS=?
IN : 0,1,1.0,2,8,10
IN : OK
OUT: AT+FCLASS=2
IN : AT+FCLASS=2
IN : OK
OUT: AT+FCR=1
IN : AT+FCR=1
IN : OK
OUT: AT+FLID="23"
IN : AT+FLID="23"
IN : OK
OUT: AT+FBOR=0
IN : AT+FBOR=0
IN : OK
OUT: AT+FDIS=?
IN : AT+FDIS=?
IN : (0,1),(0-5),(0-2),(0-2),0,0,0,(0-7)
IN : OK
OUT: AT+FDIS=1,3
IN : AT+FDIS=1,3
IN : OK
OUT: AT+FCLASS?
IN : AT+FCLASS?
IN : 2
IN : OK
OUT: AT
IN : AT
IN : OK