# HL7800 output NMEA on UART0 or UART3

**URL:** <https://forum.sierrawireless.com/t/hl7800-output-nmea-on-uart0-or-uart3/19299>\
**Category:** XS Series (GNSS)\
**Created:** [February 7, 2020, 3:20pm UTC](https://forum.sierrawireless.com/t/hl7800-output-nmea-on-uart0-or-uart3/19299 "2020-02-07T15:20:18Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![vincentkezel](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/vincentkezel/32/4982_2.png) [@vincentkezel](https://forum.sierrawireless.com/u/vincentkezel)\
**Post date:** [February 7, 2020, 3:20pm UTC](https://forum.sierrawireless.com/t/hl7800-output-nmea-on-uart0-or-uart3/19299/1 "2020-02-07T15:20:18Z")

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Hello, I am reading the datasheets before I order the HL7800-M… it’s a candidate to replace the Simcom SIM868 in my project.

I need clarification on AT+GNSSNMEA command to see if it can output on a secondary serial port. If I use **AT+GNSSNMEA: 4,1000,0,1FF** the _4_ specifies output on **same** port the command was received on. (see page 206 of AT commands guide.) Can I send that command on UART0 (pads C55,C56) or UART3 (pads C52,C54) and get the NMEA output on one of those ports, while keeping just cell modem commands on UART1 (pads C5,C6)?

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**Author:** ![cherokee](https://avatars.discourse-cdn.com/v4/letter/c/76d3ee/32.png) [@cherokee](https://forum.sierrawireless.com/u/cherokee)\
**Post date:** [February 10, 2020, 11:31am UTC](https://forum.sierrawireless.com/t/hl7800-output-nmea-on-uart0-or-uart3/19299/2 "2020-02-10T11:31:06Z")

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Hi @vincentkezel,

Could you please show information about your module by the commands below?  
ATI9  
AT+KUSBCOMP?

Thanks,

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**Author:** ![vincentkezel](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/vincentkezel/32/4982_2.png) [@vincentkezel](https://forum.sierrawireless.com/u/vincentkezel)\
**Post date:** [February 10, 2020, 10:39pm UTC](https://forum.sierrawireless.com/t/hl7800-output-nmea-on-uart0-or-uart3/19299/3 "2020-02-10T22:39:53Z")

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Thank you for your reply cherokee,  
However I do not have the HL7800-M yet… I was just wondering about the availability of nmea output to UART 0 or 3

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**Author:** ![cherokee](https://avatars.discourse-cdn.com/v4/letter/c/76d3ee/32.png) [@cherokee](https://forum.sierrawireless.com/u/cherokee)\
**Post date:** [February 11, 2020, 4:39am UTC](https://forum.sierrawireless.com/t/hl7800-output-nmea-on-uart0-or-uart3/19299/4 "2020-02-11T04:39:46Z")

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Hi vincentkezel,

UART0 and UART3 cannot be used to send command because they are dedicated for debug log.

On HL7800 module, you can send commands via UART1 or USB. UART1 and USB cannot be used simultaneously.

-With UART1: you cannot send command and get NMEA output at the same time.

-With USB : When USB mode is enable by command “AT+KUSBCOMP”, 3 USB-ACM ports are enumerated on your PC:

- USB-ACM0 - AT/PPP port
- USB-ACM1 - PPP data port
- USB-ACM2 - NMEA data port

So you can send command via USB-ACM0 and get NMEA sentences via USB-ACM2 with USB port.

Thanks,