# Proper documentation for Sierra proprietary AT commands (EM9191, EM7421, ...)?

**URL:** <https://forum.sierrawireless.com/t/proper-documentation-for-sierra-proprietary-at-commands-em9191-em7421/25214>\
**Category:** MC/EM Series\
**Created:** [October 15, 2021, 11:41am UTC](https://forum.sierrawireless.com/t/proper-documentation-for-sierra-proprietary-at-commands-em9191-em7421/25214 "2021-10-15T11:41:38Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![stefanbruens](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@stefanbruens](https://forum.sierrawireless.com/u/stefanbruens)\
**Post date:** [October 15, 2021, 11:41am UTC](https://forum.sierrawireless.com/t/proper-documentation-for-sierra-proprietary-at-commands-em9191-em7421/25214/1 "2021-10-15T11:41:38Z")

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The documentation for proprietary AT commands has been lacking for quite some time, and it gets worse for every new HW generation:

- AT!LTEINFO: essentially undocumented. Some tabular data, but several columns have no obvious meaning, and undocumented coding of values: “Serving:”, columns “D” and “U”? “SCell”, columns “Mdl”, “Mul”? Everything else.
- AT!NRINFO: essentially undocumented. How are “NR5G ul MIMO:” values coded, dito for DL.
- AT!RCOMBOS: completely undocumented, only mentioned in FW release notes.

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**Author:** ![LemonGreen](https://avatars.discourse-cdn.com/v4/letter/l/82dd89/32.png) [@LemonGreen](https://forum.sierrawireless.com/u/LemonGreen)\
**Post date:** [October 18, 2021, 10:09pm UTC](https://forum.sierrawireless.com/t/proper-documentation-for-sierra-proprietary-at-commands-em9191-em7421/25214/2 "2021-10-18T22:09:11Z")

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Hi @stefanbruens ,  
The commands were not mentioned in the official document means they have not completely verified. They might be added in the further.

Thanks

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**Author:** ![stefanbruens](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@stefanbruens](https://forum.sierrawireless.com/u/stefanbruens)\
**Post date:** [October 21, 2021, 5:20pm UTC](https://forum.sierrawireless.com/t/proper-documentation-for-sierra-proprietary-at-commands-em9191-em7421/25214/3 "2021-10-21T17:20:53Z")

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!LTEINFO has been there for years now, but still no usable documentation. Are you still “verifying” it?

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**Author:** ![LemonGreen](https://avatars.discourse-cdn.com/v4/letter/l/82dd89/32.png) [@LemonGreen](https://forum.sierrawireless.com/u/LemonGreen)\
**Post date:** [October 22, 2021, 10:36am UTC](https://forum.sierrawireless.com/t/proper-documentation-for-sierra-proprietary-at-commands-em9191-em7421/25214/4 "2021-10-22T10:36:32Z")

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Hi @stefanbruens ,

> [@stefanbruens](#):
>
> !LTEINFO has been there for years now, but still no usable documentation. Are you still “verifying” it?

I know it, I talked about AT!RCOMBOS for one of the commands have not documented. BTW. I collected information that you summarized in the ticket then forwarded to the development team. They’ll review and update for the next release.

Thanks for you idea. It’s very valuable

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**Author:** ![stefanbruens](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@stefanbruens](https://forum.sierrawireless.com/u/stefanbruens)\
**Post date:** [March 23, 2022, 7:51pm UTC](https://forum.sierrawireless.com/t/proper-documentation-for-sierra-proprietary-at-commands-em9191-em7421/25214/5 "2022-03-23T19:51:43Z")

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So, finally there was some documentation added, but I wonder if anyone has actually proofread it. From “!NRINFO”

NR5G dl MIMO: NR5G ul MIMO:

Later example shows:  
NR5G dl MIMO: 0 NR5G ul MIMO: 1

So, what is “0” supposed to mean? No downlink streams? I doubt it …  
How can there uplink MIMO, when UL MIMO is not supported in FR1? (PTS: UL MIMO:· FR1: Not supported)

Tested this with FW 03.04.03.00 and 03.09.00.00. The same nonsense is repeated in !GSTATUS, btw.