# Low power with SMS Event to it wake up

**URL:** <https://forum.legato.io/t/low-power-with-sms-event-to-it-wake-up/6604>\
**Category:** Uncategorized\
**Created:** [October 13, 2023, 12:02am UTC](https://forum.legato.io/t/low-power-with-sms-event-to-it-wake-up/6604 "2023-10-13T00:02:20Z")\
**Posts on this page:** 1\
**Showing post:** 2

<div class="post-metadata">

**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.legato.io/jyijyi/32/822_2.png) [@jyijyi](https://forum.legato.io/u/jyijyi)\
**Post date:** [October 13, 2023, 12:11am UTC](https://forum.legato.io/t/low-power-with-sms-event-to-it-wake-up/6604/2 "2023-10-13T00:11:18Z")

</div>

here is how to use command to control RI pin:

> [@Controlling DCD, DTR, DSR lines by legato application](https://forum.legato.io/t/controlling-dcd-dtr-dsr-lines-by-legato-application/3944/5):
>
> Hi jyijyi, we are using the WP7607-1 [legato: 18.06.3]. On this modul, only gpioRI is supported. root@swi-mdm9x28-wp:~# echo RI \> /sys/class/gpio/export root@swi-mdm9x28-wp:~# echo DCD \> /sys/class/gpio/export sh: write error: Operation not permitted root@swi-mdm9x28-wp:~# echo DSR \> /sys/class/gpio/export sh: write error: Operation not permitted root@swi-mdm9x28-wp:~# echo DTR \> /sys/class/gpio/export sh: write error: Operation not permitted root@swi-mdm9x28-wp:~# Do you know if the D…

Here is the sample code for adding callback function by le\_sms\_AddRxMessageHandler() to monitor SMS:

> <https://github.com/legatoproject/legato-af/blob/master/apps/tools/cm/cm_sms.c>

You can double check whether it will wake up to call the callback function during sleep mode.

---

_[View the full topic](https://forum.legato.io/t/low-power-with-sms-event-to-it-wake-up/6604)._