# BC127 Reduce BLE Tx Power to \< 6 dBm

**URL:** <https://forum.sierrawireless.com/t/bc127-reduce-ble-tx-power-to-6-dbm/19919>\
**Category:** WiFi and Bluetooth Modules\
**Created:** [March 30, 2020, 10:10am UTC](https://forum.sierrawireless.com/t/bc127-reduce-ble-tx-power-to-6-dbm/19919 "2020-03-30T10:10:49Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![rolf](https://avatars.discourse-cdn.com/v4/letter/r/94ad74/32.png) [@rolf](https://forum.sierrawireless.com/u/rolf)\
**Post date:** [March 30, 2020, 10:10am UTC](https://forum.sierrawireless.com/t/bc127-reduce-ble-tx-power-to-6-dbm/19919/1 "2020-03-30T10:10:50Z")

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With the BC127 in BLE mode is it possible, to reduce the TX Power to \< 6dBm. In Beacon Mode it is possible to set the TX Power .  
Thanks

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**Author:** ![mlw](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/mlw/32/3706_2.png) [@mlw](https://forum.sierrawireless.com/u/mlw)\
**Post date:** [March 30, 2020, 10:20am UTC](https://forum.sierrawireless.com/t/bc127-reduce-ble-tx-power-to-6-dbm/19919/2 "2020-03-30T10:20:08Z")

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@rolf

It should be possible with the ‘_SET TX\_POWER xxxx_’ command as per the [user guide](https://source.sierrawireless.com/resources/airprime/hardware_specs_user_guides/bc127-melody-audio-7-user-guide/#sthash.QFRf2XGo.dpbs).

Regards

Matt

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<div class="post-metadata">

**Author:** ![rolf](https://avatars.discourse-cdn.com/v4/letter/r/94ad74/32.png) [@rolf](https://forum.sierrawireless.com/u/rolf)\
**Post date:** [March 31, 2020, 10:02am UTC](https://forum.sierrawireless.com/t/bc127-reduce-ble-tx-power-to-6-dbm/19919/3 "2020-03-31T10:02:29Z")

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Hi Matt

Thanks for your quick response.

I downloaded the user guid 7.x for the BC 127 but i cannot find the configuration parameter TX\_POWER. Is it hidden or not described ???

Exists the parameter TX\_POWER although in the version 6.1.5 ???

I tried GET TX\_POWER -\< ERROR 0x001A

Thanks

Rolf

![image001.jpg](https://us1.discourse-cdn.com/flex025/uploads/sierrawireless/original/2X/4/4cd8b187800f42e977e072c2f67b66ff0b8c9197.jpeg)

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<div class="post-metadata">

**Author:** ![mlw](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/mlw/32/3706_2.png) [@mlw](https://forum.sierrawireless.com/u/mlw)\
**Post date:** [March 31, 2020, 12:10pm UTC](https://forum.sierrawireless.com/t/bc127-reduce-ble-tx-power-to-6-dbm/19919/4 "2020-03-31T12:10:28Z")

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@rolf,

I was looking at an internal page and did not ralise it was not in the external manual. It seems to be an undocumented command so technically not supported, as long as you use it on that basis then you should be fine.

The format is as per below.  
TX\_POWER []

I am running 7.2 firmware  
TX\_POWER  
TX\_POWER 4 8  
OK

The module uses this for page, inquiry and their scan responses. Also used as initial power for new ACL (Asynchronous Connection-Less) links.

The maximum transmit power is referenced when increasing transmit power. If transmit power on a link is already above this level, the new value does not take effect until an attempt is made to increase the power

Value set is rounded down to the next available value in the power table (-20, -16, -12, -8, -4, 0, 4, 8). Therefore, the value returned using ‘Get’ format may be lower than the value entered in the ’Set’ format.

If no parameters are provided, the default and maximum transmit power are returned (as per my test above).

Regards

Matt