# BLE Characteristic UUID issues sending Data

**URL:** <https://community.thunkable.com/t/ble-characteristic-uuid-issues-sending-data/3334160>\
**Category:** BLE / BlueTooth\
**Tags:** bluetooth\
**Created:** [November 10, 2024, 3:31pm UTC](https://community.thunkable.com/t/ble-characteristic-uuid-issues-sending-data/3334160 "2024-11-10T15:31:42Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![ioannis](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/ioannis/32/146956_2.png) [@ioannis](https://community.thunkable.com/u/ioannis)\
**Post date:** [November 11, 2024, 10:55pm UTC](https://community.thunkable.com/t/ble-characteristic-uuid-issues-sending-data/3334160/4 "2024-11-11T22:55:27Z")

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Hi @rhino-led  
Use this as your UUID: 00002A58-0000-1000-8000-00805F9B34FB

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 2A58

[Similar post](https://community.thunkable.com/t/trying-to-connect-bluetooth-bp-cuff-but-struggling-with-the-characteristic-uuid-stuff/1849525/4)

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