# Disable/Enable SIM card

**URL:** https://forum.sierrawireless.com/t/disable-enable-sim-card/1457
**Category:** Open AT
**Created:** [July 19, 2007, 5:04pm UTC](https://forum.sierrawireless.com/t/disable-enable-sim-card/1457 "2007-07-19T17:04:34Z")
**Posts on this page:** 5
**Page:** 1

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### Author: ![gdt](https://avatars.discourse-cdn.com/v4/letter/g/7993a0/32.png) [@gdt](https://forum.sierrawireless.com/u/gdt)
#### Post date: [July 19, 2007, 5:04pm UTC](https://forum.sierrawireless.com/t/disable-enable-sim-card/1457/1 "2007-07-19T17:04:34Z")

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Hi everyone,

I have some problems with an operator who seems to ‘crash’ some sim card when doing triangulation to have the device’s position.

The operator tell us that a solution consist to remove the sim and replace it after. a kind of power off power on on the sim…

I must do that with the openat… can i control the sim vcc with at commands?

Thanks in advance for suggestions

Best regards,

gdt

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### Author: ![Anjey](https://avatars.discourse-cdn.com/v4/letter/a/96bed5/32.png) [@Anjey](https://forum.sierrawireless.com/u/Anjey)
#### Post date: [July 20, 2007, 7:07am UTC](https://forum.sierrawireless.com/t/disable-enable-sim-card/1457/2 "2007-07-20T07:07:08Z")

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I think you can put something like transistor and control power throw one of GPIO putting it in high or low.

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### Author: ![gdt](https://avatars.discourse-cdn.com/v4/letter/g/7993a0/32.png) [@gdt](https://forum.sierrawireless.com/u/gdt)
#### Post date: [July 20, 2007, 11:18am UTC](https://forum.sierrawireless.com/t/disable-enable-sim-card/1457/3 "2007-07-20T11:18:43Z")

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Thanks Anjey,

The problem for us is that the pcb exists and we have no gpio available on the design. I will prefer software solution if possible…  
Thanks for your quick reply,

Best regards,

gdt

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### Author: ![jan](https://avatars.discourse-cdn.com/v4/letter/j/ce7236/32.png) [@jan](https://forum.sierrawireless.com/u/jan)
#### Post date: [July 20, 2007, 12:52pm UTC](https://forum.sierrawireless.com/t/disable-enable-sim-card/1457/4 "2007-07-20T12:52:14Z")

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Hi gdt,

I think the only “software solution” would be AT+CPOF. This will turn off the module (only if the on/off PIN is not ON all the time) thus also shut down power to the SIM, but you’ll need to manually turn on the module again (unless you have some external circuit that controls the on/off Pin).

Best Regards,  
Jan

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### Author: ![gdt](https://avatars.discourse-cdn.com/v4/letter/g/7993a0/32.png) [@gdt](https://forum.sierrawireless.com/u/gdt)
#### Post date: [July 20, 2007, 2:07pm UTC](https://forum.sierrawireless.com/t/disable-enable-sim-card/1457/5 "2007-07-20T14:07:13Z")

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Hi Jan,

To complicate a little more the problem, the device is installed in the dashboard of many trucks. We must have automatic software solution without any operator manipulation…

If I do an at+cfun=1, the wavecom power off the sim card. I will do this after 20 retries of reconnection. I hope that it will solve the problem.

Thanks for all replies

Best regards,

gdt