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LG-5350 CDMA Phone (USB) with Linux

By  Sean Reifschneider Date November 25, 2004

Summary

This phone has been reported to work quite well with Linux. In fact, this phone seems to be somewhat ideal, because the USB cable can be attached at the same time as the phone is in the charging cradle. Unfortunately, the headset can't be... Also, I believe that this only works for the home charger -- the auto charger uses the same connector on the phone, which will prevent them both from being used at the same time.

The benefit of being able to use the charger and USB at the same time is that if you can't charge while using USB you will be limited to a single charge worth of net operation. While using it in the cradle should allow unlimited sessions.

USB Cable Options

Apparently there are two cable options for this phone. Sprint used to sell a USB cable, which has since been discontinued. This apparently makes a true USB connection from the laptop to the phone. The other cable is available from Radio Shack for $20, and has a USB serial adapter built into the cable. This cable actually converts the signal from USB to regular RS-232 serial connection for the phone.

The type of cable you have will dictate how you configure the phone in the next section.

Phone Configuration

You will have to configure the phone based on the type of USB cable you have. See the previous section for information on determining that. The short form is that if you have the true USB cable, you have to set the phone for USB, if you have the Radio Shack cable, you will have to set the phone for RS-232.

Below shows the set of menu options you need to take and the options and their values that need to be setup.

Testing the connection

Once you have the phone and the computer set up properly, you should be able to plug the phone in and have "dmesg" or "/var/log/messages" show that the phone is detected. For the Radio Shack cable, for example:

   [2] guin:jafo# tail -f /var/log/messages
   Apr 18 18:51:47 guin kernel: usbserial.c: PL-2303 converter detected
   Apr 18 18:51:47 guin kernel: usbserial.c: PL-2303 converter now attached to ttyUSB0 (or usb/tts/0 for devfs)
   Apr 18 18:51:50 guin /etc/hotplug/usb.agent: Setup pl2303 for USB product 67b/2303/202

So, in this case the phone is showing up on "/dev/usb/ttyUSB0" on my KRUD/RedHat 9 system. At this point you should be able to open up a terminal emulator (such as "minicom" or "kermit"), and set it to use "/dev/usb/ttyUSB0" at 230400, and if you type "at" followed by the "enter" key, the phone should respond "OK".

DEBIAN NOTE: According to Dann Frazier, on Debian the serial device is "/dev/ttyUSB0", and the chat scripts are in "/etc/chatscripts". Dann has a Debian-oriented lg5350 script which he's submitted.

If this test fails, you probably have the phone set incorrectly for the cable type you have, or you have another problem.

Connection

Basically the phone acts just like a modem connected via USB. You will need configuration files called "/etc/ppp/peers/lg5350" and "/etc/ppp/chat-lg5350". Once you have saved these files, you can then do "pppd call lg5350", and after about 30 seconds you should have a connection to the net.

If the above test section succeeded, but you don't have net at this point, it's probably a PPP or otherwise a networking problem. Make sure that you have any wireless or wired network connections fully down before starting PPP, so that you don't have old gateways or other routing information in the tables.

Thanks

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