# Need Information On UART **URL:** \ **Category:** mangOH Green\ **Created:** [April 27, 2016, 8:07am UTC](https://mangoh.discourse.group/t/need-information-on-uart/50 "2016-04-27T08:07:13Z")\ **Posts on this page:** 1\ **Showing post:** 3
**Author:** ![dfrey](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/dfrey/32/303_2.png) [@dfrey](https://mangoh.discourse.group/u/dfrey)\ **Post date:** [April 27, 2016, 4:12pm UTC](https://mangoh.discourse.group/t/need-information-on-uart/50/3 "2016-04-27T16:12:27Z")
Hello again CSLEE, Although my previous message is accurate, I don’t think it will solve your problem. I forgot that UART 1 may not even be under control of the application processor. In order to give control of UART 1 to the application processor we need to send an AT command to the modem. The [mangOH Fundamentals - Linux CLI document](http://mangoh.io/docs/4118961-LinCLI%20mangOH%20Green%20Fundamentals%20v2.pdf) describes how to send an AT command in section “7.1.2 Connect to AirVantage” on page 28. In our case we want to send a different AT command. The AT command we want to sent is briefly described on this [Legato HOWTO - Customize UART](http://legato.io/legato-docs/16_01/how_to_customize_u_a_r_t.html) page. No documents, just the instructions! 1. in a terminal on the mangOH, run `microcom -E /dev/ttyAT` 2. type the command `AT!MAPUART?` to show the current UART configuration. The value is interpreted as `UART1Routing,UART2Routing`. 3. type the command `AT!MAPUART=17,1` to route UART1 to “Customer Linux application” 4. type in the command `AT!MAPUART?` to confirm that the setting has changed 5. press `ctrl-x` to exit microcom 6. enter the command `reboot -n` to reboot the system Now UART 1 should be available for use by your application. It will default to Iot slot 0, but you can use the instructions from my previous message to disable UART1 or route it to IoT slot 1. --- _[View the full topic](https://mangoh.discourse.group/t/need-information-on-uart/50)._