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Option Technology Globe Trotter PCMCA card on Debian GNU/Linux

January 30th, 2008

My friend, Ramakrishnan VU2KUC, has been asking me to install necessary drivers for his Option Technology Globe Trotter PCMCA card on Debian Linux. I think he has made at least 20 phone calls for same. This morning he brought his Compaq laptop to my home and asked me to fix it. I had no other choice left.
I made a google search and found that Option does not officially support Linux. But they gave me a link
which gave a general outline.
The actual driver for this GPRS modem is at
http://sourceforge.net/projects/comgt
(Later on I found out I can apt it as apt- get install gcom)
The man page of comgt/gcom is very informative.
I inserted the card. It was recognized as a modem at ttyS2

pccard: PCMCIA card inserted into slot 0
pcmcia: registering new device pcmcia0.0
0.0: ttyS2 at I/O 0×3e8 (irq = 3) is a 16550A

I made a link to /dev/modem

#ln /dev/ttyS2 /dev/modem

Then installed wvdial and ran wvdialconf, which created a basic wvdial.conf in /etc/
# apt-get install wvdial

I tweaked /etc/wvdial.conf as below

[Dialer Defaults]
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
Init3 = AT+CGDCONT=1,”IP”,”gprssouth.cellone.in”
Modem = /dev/modem
Phone = *99***1#
Idle Seconds = 3000
Password = dummy
Modem Type = Analog Modem
Stupid Mode = 1
Compuserve = 0
Baud = 115200
Auto DNS = 1
Dial Command = ATD
Ask Password = 0
ISDN = 0
Username = dummy

“gprssouth.cellone.in ” is the APN, which you have to obtain from your service provider.
Then I did
# gcom -d /dev/ttyS2

SIM ready
Waiting for Registration..(120 sec max)
Registered on Home network: “CellOne”
Signal Quality: 15,99

This registered the SIM to the BSNL ( local provider) network

I tried to dial into the BSNL network

#wvdial
The modem connected to the Internet and I could browse.
But after 2 minutes the connection dropped suddenly. This happened several times. I examined the log and found this error message

The PPP daemon has died: Lack of LCP echo responses (exit code = 15)
–> man pppd explains pppd error codes in more detail.

It seems the gprs modem is handling the LCP request properly. I edited the /etc/ppp/peers/wvdial as below and disabled LCP echo failure

noauth
name wvdial
usepeerdns
lcp-echo-failure 0
lcp-echo-interval 0

Now the connections stays even after 2 minutes.

VU2KUC is a happy man. :)

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