Cannot get cellular GSM connection on OCG module

[Mike Goulet]

Hi,

We have the OCG module up and running and performing some “hello world” functions. However, the cellular “LinkManager” does not seem to be working. The online documentation is not yielding any obvious solutions, so we’re reaching out for help. The following is a general snippet of the Java code, mostly pulled/uncommented from one of the MultiTech examples:

Device device = new Device();

Make make = device.upload(); //make is the Make of the device

Print out device parmeters to the screen

System.out.println(“—-DEVICE INFORMATION—-“);

System.out.println(“Device Make: ” + device.getMake());

System.out.println(“Device Model: ” + device.getModel());

System.out.println(“Device Serial Number: ” + device.getSerialNumber());

System.out.println(“Hardware Version: ” + device.getHardwareVersion());

System.out.println(“Radio Type: ” + device.getRadio());

System.out.println(“Ethernet MAC Address: ” + device.getMacAddress());

System.out.println(“Device Internal Temperature(degC): ” + device.getDeviceTemperature().getCelsius() + “n”);

LinkManager link = new LinkManager(device.getRadio());

link.setResetFlag(true);

link.setDemandFlag(true);

link.setIdleTimeout(30);

link.setAPN(“SET YOUR APN FOR GSM RADIOS”);

link.start();

boolean linkValid = link.testConnection(“www.google.com”, 30000);

System.out.println(“Cellular Connection Test Successful: ” + linkValid);

Our APN is valid for our SIM – we’ve verified this using a different modem. Not sure what the dial string needs to be, but we’re connecting to an AT&T network, so I think it’s supposed to be “*99***1#”, which is what the OCG device reports by default.

We have an antenna plugged into the UMCC connector labeled “M” on the OCG module.

The call to link.testConnection() is failing. Any idea why?

Thanks,

-Mike

[Bryan Tran]

Hi Mike,

1. What is the model number of the device ?

2. First we need to check to see if we have a good signal and if we are registering to home network. SSH into your device and type:

microcom /dev/modem_at0[Enter]

AT+CSQ[Enter] <–Querying signal

AT+CREG?[Enter] <–Check to see if we are registering to home network.

Ctrl+x[Enter] <–Exiting microcom.

http://www.multitech.com/en_US/DOCUMENTS/Families/MultiConnectOCGE/manuals.aspx

3. Once we know that we have a good signal and registering to home network. We can run the pppd service manually from the command line. To do that – you need to go /etc/ppp/peers and modify the gsm_chat with your valid APN. Then save the file and run the ppp service by typing:

pppd call gsm &[Enter] <–Run pppd service

tail -f /var/log/messages[Enter] <–What is going on.

ping http://www.google.com[Enter] <–Check to see if getting replies.

4. If we are getting replied from the internet, then we need to remove/terminate the pppd call gsm process by using the kill command. Then we can try the java program again and see if it helps.

5. If you are still having a problem, then pls create a support portal case at https://support.multitech.com/support/login.html.

Regards,

BT

[Mike Goulet]

Bryan,

Sorry for the delayed response. The engineer doing the work here is on vacation until next week. We’ll try this out early next week. Will let you know how it goes.

Thanks for getting back!

-Mike

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