FAQ forum/wiki?

Another one: Connecting to I/O pins on Q2686 etc


ciao, Dave


eg, viewtopic.php?f=37&t=3986&p=15720#p15717

It’s not “garbage” - it is PPP data.
The module has been asked to create an IP connection, so it expects the external device to respond with IP packets in PPP format.
Because it doesn’t get any PPP/IP packets, it drops the call - hence giving NO CARRIER.

The modem is working correctly!


Don’t use the following code construct:

    // do something

See viewtopic.php?f=36&t=3908&start=15#p16093 amongst others.

ciao, Dave

See also: viewtopic.php?f=23&t=3922&p=16688#p15350

Example: viewtopic.php?f=16&t=4204&p=16686#p16686


Looks like a number of users are having strange or intermittent issues with their modules that end up being resolved by fixing the module PSU.

See here and here for a couple of examples.

Of course, there’s also the Power Supply forum to peruse as well.

ciao, Dave

Yes, I’ve had such issues myself!

It’s not just the PSU itself - the connections to the module (especially ground) need to be absolutely “solid”

Example: viewtopic.php?f=123&t=5693&p=23827&hilit=vbatt+line+too+narrow#p23826

This is because all GSM devices have a very high supply current peaks - Wavecom quote over 2A! :open_mouth:

Just noted that I have already mentioned “Module Grounding” in an earlier suggestion in this thread!

An increasing number of people are now asking about C++





Another example: viewtopic.php?f=74&t=4252&p=17077#p17075

And another: viewtopic.php?f=78&t=4285&p=17090#p17088

If the unit fails to register, check the Frequency Band setting - especially after a firmware update

see: viewtopic.php?f=53&t=4332#p17345

But note that R7.4 opens the USB port automatically - this is a change from earlier firmware.


Yet another common problem: Trying to make calls/connect to GPRS before SIM is initalised and network registered.

Always check SIM state and Network Registration before attempting network operations.

Check for SIM_FULL_INIT and +CREG: 1 responses…

for a couple of examples

ciao, Dave

In fact, trying to do anything network-related before the network is ready!

SMS is another key one…

This one, of course, is not Wavecom-specific.


For example, see:



i don’t know if i agree entirely,
the latest firmware editions try to start you application 8 times and if it still crashes the 8th time, they give up on it.

What editions, specifically?

Is that actually documented?

But there are still people using firmware versions without this feature: viewtopic.php?f=19&t=4486

i’m fairly certain that this mechanism is functional since 7.x

yes, see ‘Description / Recovery Mechanism’ in the ADL user guide

i know, and for these people it’s still helpful.

The requirement that an application has to be built for a firmware version that matches the firmware physically installed on the device.
(in general, “matches” means “the same as”).

It’s a bit like making an application for a PC: if you build the application to run on Vista, it won’t work on Win-95

The response to AT+WOPEN=2 shows both the firmware version physically installed on the device, and the version for which the currently-loaded application was built:

In general, the two numbers need to be the same.