# Trying to connect Bluetooth BP cuff, but struggling with the "characteristic UUID" stuff

**URL:** <https://community.thunkable.com/t/trying-to-connect-bluetooth-bp-cuff-but-struggling-with-the-characteristic-uuid-stuff/1849525>\
**Category:** BLE / BlueTooth\
**Tags:** bluetooth\
**Created:** [April 26, 2022, 1:57pm UTC](https://community.thunkable.com/t/trying-to-connect-bluetooth-bp-cuff-but-struggling-with-the-characteristic-uuid-stuff/1849525 "2022-04-26T13:57:07Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![muneer](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/muneer/32/75210_2.png) [@muneer](https://community.thunkable.com/u/muneer)\
**Post date:** [April 26, 2022, 2:27pm UTC](https://community.thunkable.com/t/trying-to-connect-bluetooth-bp-cuff-but-struggling-with-the-characteristic-uuid-stuff/1849525/4 "2022-04-26T14:27:28Z")

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> [@multitech-visions](#):
>
> May I ask how you got all the extra characters?

This is the default or base UUID for all characteristic IDs if not set by the factory.

The default is 00000000-0000-1000-8000-00805F9B34FB  
If the manufacturer is giving you only 4 digit then it is assumed that you need to use the default UUID. It starts with 8 hexadecimal digits and you need to add your 4 digit hexadecimal number as the second part of it. So instead of all zeros it would be 0000 plus your code FFF4

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