当 PPP 尝试与模块建立通信时，我在日志文件中收到此消息：
Serial connection established.
using channel 6
Using interface ppp0
Connect: ppp0 <--> /dev/ttyO5
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xc83c6fe3>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xc83c6fe3>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xc83c6fe3>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xc83c6fe3>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xc83c6fe3>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xc83c6fe3>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xc83c6fe3>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xc83c6fe3>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xc83c6fe3>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xc83c6fe3>]
LCP: timeout sending Config-Requests
Connection terminated.
Receive serial link is not 8-bit clean:
Problem: all had bit 7 set to 0
Modem hangup
该模块似乎没有响应 LCP 请求，我不明白为什么。
我的 /etc/ppp/options 文件是：
lock
crtscts
defaultroute
noauth
hide-password
noipdefault
default-asyncmap
我的聊天文件是：
ABORT "BUSY"
ABORT "NO CARRIER"
ABORT "Username/Password Incorrect"
SAY "Starting chat file \n"
'' AT
SAY "\n ATE0"
OK ATE0
SAY "\n AT#SELINT=2"
OK AT#SELINT=2
SAY "\n AT+IPR=57600"
OK AT+IPR=57600
SAY "\n AT&K3"
OK AT&K3
SAY "\n AT+CMEE=2"
OK AT+CMEE=2
SAY "\n AT+CPIN=6512"
OK AT+CPIN=6512
SAY "\n Logging in...."
OK AT+CGDCONT=1,"IP","internet.vodafone.pt","0.0.0.0",0,0
OK AT#USERID="vodafone"
OK AT#PASSW="vodafone"
SAY "\n AT#GPRS=1"
OK AT#GPRS=1`
SAY 字符串仅用于日志跟踪。