We have got more and more customers that send their units with an AirPrime Q2687 back for repair, claiming that those units do not connect to the network anymore. Those units have been in operation for years without any problem, this issue was noticed only recently.
As our repair center could not find a problem in the units, I took out the Q2687 module and put it onto an evaluation kit. the firmware our customers use is 7.45, however, just to note this right here, I updated the firmware to 7.52 and the behavior was the same.
(The reason we are still on 7.45 is the following: On those modules, update to 7.52 via XMODEM fails with an error, but this is another topic.)
The problem seems to be that, from power up, the network registration time can be as short as 4 minutes (what, in my option, is actually already long) but sometimes goes up to 30 minutes!
At my workplace, there are 5 networks visible, one has no 2G access, two are forbidden, and the other two have still 2G support. The home network of the SIM card is one of them, which is Vodaphone.
After registration is done, the signal level seems reasonable at level 14 (=-85dBm).
I’ve created a batch file that logs the network status ever 5 seconds. It starts with this entry:
continues like this till the module has registered:
Why could it be, that network registration takes such a long time?
Could this be related to more and more 3G, 4G and even 5G networks being around?
Is there and way to speed up this network registration?
Is there anything I can go to get more information on this issue?