MTCDP-H5-GP-1.0 ppp connection

[David Blanco]

Hi everybody, I’m new in the forum and first of all congratulations for you collaboration in this great tool. I’d really appreciate if somebody could help me:

We have an MultiConnect OCG modem and we have used a VODAFONE SIM for the tests performed.

Problems with the ppp connection

steps followed to setup the ppp connection in the OCG modem (H5, cdma):

a. device port for the OCG, modified in the file /etc/ppp/options –> /dev/modem_at0 (also it has been performed the same test with /dev/ttyACM0)

b. the cdma and cdma_chat files (/etc/ppp/peers/) have not been modified

c. it has been used the command: pppd call cdma

d. then, it has been executed the command “ip a” to see the available connections and the ppp link doesn’t appear.

The debug option is enabled, and a log file is generated. The error that appears is
CDMA chat
Dialing…
Waiting for CONNECT…
Script /usr/sbin/chat -v -t 90 -f /etc/ppp/peers/cdma_chat finished (pid 729), status = 0x7
Connect script failed

Then, some AT commands has been tested correctly like received a call and hang out. Read the quality link (+CSQ: 15,2), but we are trying to make a voice call and the response is “NO CARRIER”

So what could be the problem with the ppp link? I attached the configuration files of the device.

cdma.txt:
linkname ppp0
230400
debug
logfile /tmp/logppp
defaultroute
replacedefaultroute
usepeerdns
noauth
crtscts
novj
connect ‘/usr/sbin/chat -v -t 90 -f /etc/ppp/peers/cdma_chat’

cdma_chat.txt:
SAY “CDMA chat\n”
ECHO OFF
ABORT ‘NO DIAL TONE’
ABORT ‘NO DIALTONE’
ABORT ‘NO ANSWER’
ABORT ‘NO CARRIER’
ABORT ‘DELAYED’
ABORT ‘VOICE’
ABORT ‘BUSY’
” ‘AT’
OK ‘ATZ’
OK ‘AT+CSQ’
SAY “Dialing…\n”
OK ‘ATD#777’
SAY “Waiting for CONNECT…\n”
TIMEOUT 120
CONNECT ”
SAY “Connected\n”

options.txt:
# Select tty device
#/dev/ttyACM0

# First modem AT command port (symlink to actual device)
/dev/modem_at0

# Uncomment below to run in foreground
nodetach

# Uncomment below to emit debug
debug

# Uncomment to keep pppd up if the connection terminates
#persist
# Uncomment for unlimited connection attempts
#maxfail 0

lock

Many thanks,
David.

[Lonny Knudson]

Hi David,
For the -H5 devices you should be using the gsm peer file and chat script. You will need to modify the gsm chat script so that the +CGDCONT command references the APN you need to use for the Vodafone account.
If you have trouble when using the gsm files, please post a copy of syslog events during the attempt to start pppd.

[David Blanco]

Hi Lonny,
Thank you for your quick answer. You were right, I configured it as a GSM device and now it works fine.
My next issue to deal with is that I can not get access to the device remotely.I need to create an SSH connection to the modem from the ppp interface. I need a public IP establish that connection. Could you tell me how can I obtain that address? Is an static IP address strictly needed?
Thanks again,
David.

Below I attached the result of some executed commands
# pppd call gsm &
# ping -c 1 http://www.google.com
# wget -q -O – http://checkip.dyndns.org|sed -e ‘s/.*Current IP Address: //’ -e ‘s/<.*$//’
# ifconfig

# pppd call gsm &
[1] 1298
# GSM chat
Dialing…
Waiting for CONNECT…
Connected
Script /usr/sbin/chat -v -t 90 -f /etc/ppp/peers/gsm_chat finished (pid 1301), status = 0x0
Serial connection established.
using channel 5
Using interface ppp0
Connect: ppp0 <–> /dev/modem_at0
rcvd [LCP ConfReq id=0x1 <asyncmap 0x0> <auth pap> <magic 0x96a24aa4> <pcomp> <accomp>]
Warning – secret file /etc/ppp/pap-secrets has world and/or group access
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xa4227644> <pcomp> <accomp>]
sent [LCP ConfAck id=0x1 <asyncmap 0x0> <auth pap> <magic 0x96a24aa4> <pcomp> <accomp>]
rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0xa4227644> <pcomp> <accomp>]
Warning – secret file /etc/ppp/pap-secrets has world and/or group access
sent [PAP AuthReq id=0x1 user=”mtcdp” password=<hidden>]
rcvd [PAP AuthAck id=0x1 “”]
PAP authentication succeeded
kernel does not support PPP filtering
sent [CCP ConfReq id=0x1 <deflate 15> <deflate(old#) 15> <bsd v1 15>]
sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
rcvd [LCP ProtRej id=0x2 80 fd 01 01 00 0f 1a 04 78 00 18 04 78 00 15]
Protocol-Reject for ‘Compression Control Protocol’ (0x80fd) received
rcvd [IPCP ConfNak id=0x1 <ms-dns1 10.11.12.13> <ms-dns2 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>]
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>]
sent [IPCP ConfReq id=0x4 <addr 0.0.0.0> <ms-dns1 10.11.12.13> <ms-dns2 10.11.12.14>]
rcvd [IPCP ConfNak id=0x4 <ms-dns1 10.11.12.13> <ms-dns2 10.11.12.14>]
sent [IPCP ConfReq id=0x5 <addr 0.0.0.0> <ms-dns1 10.11.12.13> <ms-dns2 10.11.12.14>]
rcvd [IPCP ConfReq id=0x1]
sent [IPCP ConfNak id=0x1 <addr 0.0.0.0>]
rcvd [IPCP ConfNak id=0x5 <addr 10.53.95.255> <ms-dns1 212.166.132.117> <ms-dns2 212.73.32.67>]
sent [IPCP ConfReq id=0x6 <addr 10.53.95.255> <ms-dns1 212.166.132.117> <ms-dns2 212.73.32.67>]
rcvd [IPCP ConfReq id=0x2 <addr 10.53.95.255>]
sent [IPCP ConfAck id=0x2 <addr 10.53.95.255>]
rcvd [IPCP ConfAck id=0x6 <addr 10.53.95.255> <ms-dns1 212.166.132.117> <ms-dns2 212.73.32.67>]
local IP address 10.53.95.255
remote IP address 10.53.95.255
primary DNS address 212.166.132.117
secondary DNS address 212.73.32.67
Script /etc/ppp/ip-up started (pid 1314)
Script /etc/ppp/ip-up finished (pid 1314), status = 0x0

# ping -c 1 http://www.google.com
PING http://www.google.com (173.194.41.209): 56 data bytes
64 bytes from 173.194.41.209: seq=0 ttl=54 time=78.798 ms

— http://www.google.com ping statistics —
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 78.798/78.798/78.798 ms

# wget -q -O – http://checkip.dyndns.org|sed -e ‘s/.*Current IP Address: //’ -e ‘s/<.*$//’
31.4.222.127

# ifconfig
eth0 Link encap:Ethernet HWaddr 00:08:00:87:9D:8F
inet addr:10.0.3.235 Bcast:10.0.3.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:37281 errors:0 dropped:0 overruns:0 frame:0
TX packets:5573 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:4205316 (4.0 MiB) TX bytes:1393960 (1.3 MiB)
Interrupt:21 Base address:0x4000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:32 errors:0 dropped:0 overruns:0 frame:0
TX packets:32 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2208 (2.1 KiB) TX bytes:2208 (2.1 KiB)

ppp0 Link encap:Point-to-Point Protocol
inet addr:10.53.95.255 P-t-P:10.53.95.255 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1
RX packets:23 errors:0 dropped:0 overruns:0 frame:0
TX packets:28 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
RX bytes:1826 (1.7 KiB) TX bytes:1508 (1.4 KiB)

[Lonny Knudson]

Hi David,
If you need to access your device from the internet, you will need to work with the cellular provider. The log showing your ppp connection shows that your provider is assigning your device a private IP address which is not available on the public internet. Your provider may be able to assign your account a public and/or static IP for remote access applications.

[David Blanco]

Hi Lonny,
Thank you for your help. I’ll contact the cellular provider.
BR,
David.

[Author]

Posts