# Trying to figure which UUIDs on device to use

**URL:** <https://community.thunkable.com/t/trying-to-figure-which-uuids-on-device-to-use/2758219>\
**Category:** Questions about Thunkable X\
**Created:** [December 23, 2023, 3:22am UTC](https://community.thunkable.com/t/trying-to-figure-which-uuids-on-device-to-use/2758219 "2023-12-23T03:22:09Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![steve\_synopsis](https://avatars.discourse-cdn.com/v4/letter/s/48db29/32.png) [@steve\_synopsis](https://community.thunkable.com/u/steve_synopsis)\
**Post date:** [December 23, 2023, 3:22am UTC](https://community.thunkable.com/t/trying-to-figure-which-uuids-on-device-to-use/2758219/1 "2023-12-23T03:22:09Z")

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Hi,

I have a terminal with a built-in printer and trying to get BLE to connect to the printer. When I run the Lightblue app, the printer shows up under Bonded, and the screens that I get are below. I tried connecting to the UUID under Generic Access as well as Service Changed UUID but Thunkable crashes - error log attached.

I can get the printer to work directly from Lightblue by going under Writable without response, switching to UTF-8 and then sending text.

 ![UUIDs](https://us1.discourse-cdn.com/flex015/uploads/thunkable/original/3X/a/8/a88db5239f6161804cf1e33b60e032ab2bf920c4.jpeg)

Would appreciate any assistance getting this printer to work.

Thanks  
Steve

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**Author:** ![steve\_synopsis](https://avatars.discourse-cdn.com/v4/letter/s/48db29/32.png) [@steve\_synopsis](https://community.thunkable.com/u/steve_synopsis)\
**Post date:** [December 24, 2023, 12:52pm UTC](https://community.thunkable.com/t/trying-to-figure-which-uuids-on-device-to-use/2758219/2 "2023-12-24T12:52:26Z")

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@muneer Can you lend some guidance?

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<div class="post-metadata">

**Author:** ![steve\_synopsis](https://avatars.discourse-cdn.com/v4/letter/s/48db29/32.png) [@steve\_synopsis](https://community.thunkable.com/u/steve_synopsis)\
**Post date:** [December 25, 2023, 1:11am UTC](https://community.thunkable.com/t/trying-to-figure-which-uuids-on-device-to-use/2758219/3 "2023-12-25T01:11:24Z")

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It turns out, although it not mentioned anywhere in the documentation, that you can connect by using the MAC address as the device ID.

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**Author:** ![system](https://us1.discourse-cdn.com/flex015/uploads/thunkable/original/3X/0/f/0f59f292712368bce16ff80133ae10de8a6f27e8.png) [@system](https://community.thunkable.com/u/system)\
**Post date:** [March 24, 2024, 1:11am UTC](https://community.thunkable.com/t/trying-to-figure-which-uuids-on-device-to-use/2758219/4 "2024-03-24T01:11:58Z")

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