Switch off SIM

I would like to manage a double sim, so that I can switch between two different operators, i.e. when the signal is too low.
In order to to that I used a switch that moves the SIM-IO and the SIMPRES IO from one sim to the other.
The switch can be managed by a gpo.

If I switch the SIM the modem cannot realize that something actually changed, and sometimes crashes.
It seems that, although I use the SIMPRESS directly (or drived by a gpo, in series after the simpress wire ) the modem realize that one sim is present, regardless by the value of the simpress itself.
How the modem realize that a sim is inserted and when is removed? (ADL_SIM_EVENT_INSERTED and ADL_SIM_EVENT_REMOVED events)?

I think that I need to “switch off” the sim, switch the SIM-IO and the SIMPRESS on the other sim and then “switch on” the sim. Is there any AT command that let me force the reinit of a sim, without resetting the modem?

Thank you very much for any hint.

I use a 6.02.02 OS on a R71a01gg.Q2686H.

Are you simply switching SIMPRES between the two SIMs, or are you forcing it low for some amount of time? I assume that if SIMPRES was forced low for a while before connecting it to the new SIM, then the Q2686 would just think you phisically swapped SIM cards.

Rather than just guess how long might be needed for “for a while”, why not wait for the “SIM Removed” event, and only connect the other SIM after that?


  1. Disconnect 1st SIM;
  2. Wait for “SIM Removed”;
  3. Connect 2nd SIM;
  4. Wait for “SIM Inserted”;
  5. Game on with new SIM…

Ohh! Good idea! For my application SIMPRES is hard-wired high, so I never play with such things.

I works, thank you! :smiley:

Im having some trouble to do DUAL SIM. In mi case, im using the SIMPRESS driven with an 1.8V Output. But, unforntunaletly im always receiving a SIM STATE REMOVED.

Im using a Q2687H with the R74 Firm.
And my sequence is like this.

  1. I detected one or two SIMS by two inputs.
  2. I write in the 1.8Output a “1”.
  3. I choose wich SIM i would to manage with an output (this manage all the hardware SIM selection).
  4. I suscribe to the SIM services.
  5. I receive a SIM STATE REMOVED.

I am doing something wrong??, i cant find any problems with the hardware. And i could find any documentation about this.

Can you help me?.

Best Regards, Nicolas.