pppd拨号的问题

arm linux移植的pppd 和chat来实现的，通过ppp-on脚本拨号，貌似前面connect成功了，但是随后的LCP请求总是无法收到东西，重发10次后就timeout退出了。

Jan 1 00:04:15 mobile_trex1 daemon.info pppd[404]: Serial connection established.
Jan 1 00:04:15 mobile_trex1 daemon.debug pppd[404]: using channel 1
Jan 1 00:04:15 mobile_trex1 daemon.info pppd[404]: Using interface ppp0
Jan 1 00:04:15 mobile_trex1 daemon.notice pppd[404]: Connect: ppp0 <--> /dev/ttyTX2
Jan 1 00:04:16 mobile_trex1 daemon.debug pppd[404]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x92c99030> <pcomp> <accomp>]
Jan 1 00:04:19 mobile_trex1 daemon.debug pppd[404]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x92c99030> <pcomp> <accomp>]
Jan 1 00:04:22 mobile_trex1 daemon.debug pppd[404]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x92c99030> <pcomp> <accomp>]
Jan 1 00:04:25 mobile_trex1 daemon.debug pppd[404]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x92c99030> <pcomp> <accomp>]
Jan 1 00:04:28 mobile_trex1 daemon.debug pppd[404]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x92c99030> <pcomp> <accomp>]
Jan 1 00:04:31 mobile_trex1 daemon.debug pppd[404]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x92c99030> <pcomp> <accomp>]
Jan 1 00:04:34 mobile_trex1 daemon.debug pppd[404]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x92c99030> <pcomp> <accomp>]
Jan 1 00:04:37 mobile_trex1 daemon.debug pppd[404]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x92c99030> <pcomp> <accomp>]
Jan 1 00:04:40 mobile_trex1 daemon.debug pppd[404]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x92c99030> <pcomp> <accomp>]
Jan 1 00:04:43 mobile_trex1 daemon.debug pppd[404]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x92c99030> <pcomp> <accomp>]
Jan 1 00:04:46 mobile_trex1 daemon.warn pppd[404]: LCP: timeout sending Config-Requests 
Jan 1 00:04:46 mobile_trex1 daemon.notice pppd[404]: Connection terminated.
Jan 1 00:04:46 mobile_trex1 daemon.notice pppd[404]: Modem hangup
Jan 1 00:04:46 mobile_trex1 daemon.info pppd[404]: Exit.


大致问题出现在哪里呢 有无人指点一下

通讯的环境是 pc--->modem----<---modem-----<pc