Hi,

I have problem to connect pppd to my ISP.
On my machine is used GSM modem which supports multiplexer protocol (sharing physical serial port to several "virtual" serial ports). When I use pppd with physical serial port (/dev/ttyS0), all is OK and can get IP address and new device ppp0 is up. But when I use gsmMuxd which creates two virtual serial ports, then pppd accepts "CONNECT" and nothing more even it sends LCP packet Config-Requests. When I debug gsmMuxd I am seeing that it passes received LCP packets from /dev/ttyS0 to virtual port /dev/mux0 to pppd, but pppd denies them for unknown reason. Pppdump says that "CONNECT" string is last what is accepted and other packets are not received by pppd. Any tips, ideas ?

My pppd config file:
/dev/mux0 19200
connect '/usr/sbin/chat -v -s -e -f /etc/ppp/chat-gprs'
modem -detach
noccp
defaultroute
usepeerdns
noauth
ipcp-accept-remote
ipcp-accept-local
noipdefault

There is debug output of my pppd:

mymachinename:/etc/ppp/peers# pppd debug record init_mux_dump.txt call plus &
[1] 8343
mymachinename:/etc/ppp/peers# send (AT+CGDCONT=1,"IP","internet"^M)
expect (OK)
AT+CGDCONT=1,"IP","internet"
AT+CGDCONT=1,"IP","internet"^M^M
OKOK
-- got it

send (ATD*99***1#^M)
expect (CONNECT)

^M
ATD*99***1#
ATD*99***1#^M^M
CONNECTCONNECT
-- got it

send (^M)

Serial connection established.
using channel 10
Using interface ppp0
Connect: ppp0 <--> /dev/pts/13
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x333b8564> <pcomp> <accomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x333b8564> <pcomp> <accomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x333b8564> <pcomp> <accomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x333b8564> <pcomp> <accomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x333b8564> <pcomp> <accomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x333b8564> <pcomp> <accomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x333b8564> <pcomp> <accomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x333b8564> <pcomp> <accomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x333b8564> <pcomp> <accomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x333b8564> <pcomp> <accomp>]
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

Peter

I found reason of this problem in my pppd <-> modem communication. GSM modem MO200 which I use, supports multiplexer protocol by strange way. It uses virtual channel 1 for modem commands and virtual channel 2 for data. So that was the reason, "CONNECT" was received through virtual channel 1 but following data modem sends to channel 2.

Peter

Can you provide some more details on how you fixed this? Am getting a very similar error with a Huawei UMG1831 GSM modem.

Thank you,
Ron