我正在使用Telit UC864-E GSM 3G调制解调器。我想使用pppd（ppp守护进程）在linux上通过PPP运行GPRS / 3G连接。
我的开发板上有一个Telit UC864-E调制解调器，在Atmel SAM9微处理器上运行嵌入式Linux。调制解调器连接到SAM9，我已经通过从SAM9上的测试程序执行AT命令来测试它。甚至GPRS / 3G也可以使用测试应用程序正常工作。但是，我无法在此板上的嵌入式Linux上通过ppp建立数据连接。这是日志：
# pppd call gprs
Press CTRL-C to close the connection at any stage!
defining PDP context...
AT
OK
ATZ
OK
ATE1
OK
AT+CGDCONT=1,"IP","www",,0,0
OK
Serial connection established.
using channel 1
Using interface ppp0
Connect: ppp0 <--> /dev/ttyS3
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x43ee1a75>]
rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x43ee1a75>]
rcvd [LCP ConfReq id=0x1 <asyncmap 0x0> <auth pap> <magic 0xd2b80f00> <pcomp> <]
No auth is possible
sent [LCP ConfRej id=0x1 <auth pap> <pcomp> <accomp>]
rcvd [LCP TermReq id=0x2 00 00 00 00 00 00]
sent [LCP TermAck id=0x2]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x43ee1a75>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x43ee1a75>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x43ee1a75>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x43ee1a75>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x43ee1a75>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x43ee1a75>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x43ee1a75>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x43ee1a75>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x43ee1a75>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x43ee1a75>]
LCP: timeout sending Config-Requests
Connection terminated.
Modem hangup
我有一个相同调制解调器的评估板，它连接到运行linux（ubuntu）的台式机上，我已成功运行pppd来访问互联网。这是日志：
harsh@ubuntu:~$ sudo pppd call gprs
Press CTRL-C to close the connection at any stage!
defining PDP context...
AT
OK
ATZ
OK
ATE1
OK
AT+CGDCONT=1,"IP","www",,0,0
OK
Script /etc/ppp/peers/gprs-connect finished (pid 3723), status = 0x0
Serial connection established.
using channel 3
Using interface ppp0
Connect: ppp0 <--> /dev/ttyS0
Warning - secret file /etc/ppp/pap-secrets has world and/or group access
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x8579ad41>]
rcvd [LCP ConfReq id=0x5 <asyncmap 0x0> <auth chap MD5> <magic 0xdab06202> <pcomp> <accomp>]
sent [LCP ConfRej id=0x5 <pcomp> <accomp>]
rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x8579ad41>]
rcvd [LCP ConfReq id=0x6 <asyncmap 0x0> <auth chap MD5> <magic 0xdab06202>]
sent [LCP ConfNak id=0x6 <auth pap>]
rcvd [LCP ConfReq id=0x7 <asyncmap 0x0> <auth pap> <magic 0xdab06202>]
sent [LCP ConfAck id=0x7 <asyncmap 0x0> <auth pap> <magic 0xdab06202>]
sent [LCP EchoReq id=0x0 magic=0x8579ad41]
Warning - secret file /etc/ppp/pap-secrets has world and/or group access
sent [PAP AuthReq id=0x1 user="ubuntu" password=""]
rcvd [LCP DiscReq id=0x8 magic=0xdab06202]
rcvd [PAP AuthAck id=0x1 ""]
PAP authentication succeeded
sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
rcvd [IPCP ConfNak id=0x1 <ms-dns1 10.11.12.13> <ms-dns2 10.11.12.14> <ms-wins 10.11.12.13> <ms-wins 10.11.12.14>]
sent [IPCP ConfReq id=0x2 <addr 0.0.0.0> <ms-dns1 10.11.12.13> <ms-dns2 10.11.12.14>]
rcvd [IPCP ConfNak id=0x2 <ms-dns1 10.11.12.13> <ms-dns2 10.11.12.14> <ms-wins 10.11.12.13> <ms-wins 10.11.12.14>]
sent [IPCP ConfReq id=0x3 <addr 0.0.0.0> <ms-dns1 10.11.12.13> <ms-dns2 10.11.12.14>]
rcvd [IPCP ConfNak id=0x3 <ms-dns1 10.11.12.13> <ms-dns2 10.11.12.14> <ms-wins 10.11.12.13> <ms-wins 10.11.12.14>]
sent [IPCP ConfReq id=0x4 <addr 0.0.0.0> <ms-dns1 10.11.12.13> <ms-dns2 10.11.12.14>]
rcvd [IPCP ConfReq id=0x2]
sent [IPCP ConfNak id=0x2 <addr 0.0.0.0>]
rcvd [IPCP ConfNak id=0x4 <addr 1.39.207.26> <ms-dns1 10.11.230.2> <ms-dns2 10.11.230.3>]
sent [IPCP ConfReq id=0x5 <addr 1.39.207.26> <ms-dns1 10.11.230.2> <ms-dns2 10.11.230.3>]
rcvd [IPCP ConfReq id=0x3]
sent [IPCP ConfAck id=0x3]
rcvd [IPCP ConfAck id=0x5 <addr 1.39.207.26> <ms-dns1 10.11.230.2> <ms-dns2 10.11.230.3>]
Could not determine remote IP address: defaulting to 10.64.64.64
not replacing existing default route via 192.168.170.2
Cannot determine ethernet address for proxy ARP
local IP address 1.39.207.26
remote IP address 10.64.64.64
primary DNS address 10.11.230.2
secondary DNS address 10.11.230.3
Script /etc/ppp/ip-up started (pid 3727)
Script /etc/ppp/ip-up finished (pid 3727), status = 0x0
“gprs”脚本在两个Linux环境中都是相同的。
可能是什么问题？