# WISMO218: AT initial sequence?

**URL:** <https://forum.sierrawireless.com/t/wismo218-at-initial-sequence/3518>\
**Category:** Legacy AirPrime modules\
**Created:** [August 2, 2009, 4:11pm UTC](https://forum.sierrawireless.com/t/wismo218-at-initial-sequence/3518 "2009-08-02T16:11:58Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![mr\_g](https://avatars.discourse-cdn.com/v4/letter/m/ecb155/32.png) [@mr\_g](https://forum.sierrawireless.com/u/mr_g)\
**Post date:** [August 2, 2009, 4:11pm UTC](https://forum.sierrawireless.com/t/wismo218-at-initial-sequence/3518/1 "2009-08-02T16:11:58Z")

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I have problem with wismo 218. It have worked for a short period of time, and only for a few seconds it responded to at+creg=? with 0,1… All other time it’s 0,3%; 0,4%…

Also, after XX number of seconds it would stop responding on AT commands…

What is the usual init sequence for wismo? I use 3 wire UART connection (just GND, TX and RX) on 115200bps…

Thank you…

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**Author:** ![blackyblack](https://avatars.discourse-cdn.com/v4/letter/b/2acd7d/32.png) [@blackyblack](https://forum.sierrawireless.com/u/blackyblack)\
**Post date:** [August 3, 2009, 6:44am UTC](https://forum.sierrawireless.com/t/wismo218-at-initial-sequence/3518/2 "2009-08-03T06:44:52Z")

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Maybe it enters in the sleep mode. There is a reference scheme for connecting wismo without DTR control. Try to reproduce it.

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**Author:** ![ignitech](https://avatars.discourse-cdn.com/v4/letter/i/bcef8e/32.png) [@ignitech](https://forum.sierrawireless.com/u/ignitech)\
**Post date:** [August 26, 2009, 7:44am UTC](https://forum.sierrawireless.com/t/wismo218-at-initial-sequence/3518/3 "2009-08-26T07:44:31Z")

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Check your filter cap. If your power supply is not sufficient, the WISMO218 will shut down when it attempts to transmit (a few seconds after power on).  
Mick.