Module hungs up or switches off during SIM reading

6 thoughts on “Module hungs up or switches off during SIM reading

  1. GE865-QUAD. Pcb from old project. Several seconds after AT#SIMDET=1,  module hungs up. It seems that it try to read. Gives me READY several times, blinking led changes blinking rate.

    Network registration is disabled. Same problem in 5 same pcbs.

    Only from time to time some of pcb can even connect to network when I enable this. 

    Sim is ok, signal level too.

    I can see all 3 bulgarian operators.


    Any Ideas?

  2. 220uF tantal on power line, Li-Ion battery 900mAh, voltage approx 3,9V.


    Module works and responds to at-commands long tome.

    Only after SIMDET=1 one module hungs up, 2 others start restarting.

    Network registration is forbidden (COPS=2).


    Poor soldering of some of SIM pads?

    One of modules do not restart but rarely. When do not restart, it can register by COPS=0.


    Signal level approx -70dBm.

  3. New module connected with wires. Same rasult – SIM is ready, but not possible to ocnnect to network.

    1. As Cosmin suggests it’s probably a power issue, most likely the  PCB power tracks to the module in particular the ground tracks, these need to as wide as you can get them.