# Fathom X tehter interface link not working

**URL:** https://discuss.bluerobotics.com/t/fathom-x-tehter-interface-link-not-working/20380
**Category:** Communication Interfaces
**Created:** [May 15, 2025, 9:01am UTC](https://discuss.bluerobotics.com/t/fathom-x-tehter-interface-link-not-working/20380 "2025-05-15T09:01:02Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![manci](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@manci](https://discuss.bluerobotics.com/u/manci)
#### Post date: [May 15, 2025, 9:01am UTC](https://discuss.bluerobotics.com/t/fathom-x-tehter-interface-link-not-working/20380/1 "2025-05-15T09:01:02Z")

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Dear friends,

I have lost communication from the Qground control to the BlueRoV2. The ground Fathom X board shows the power led on all the time but the link led blinks at power on but then it is off all the time.

On the ROV fathom X board, the link led is on for about 14 seconds after power on, but then it turns off. I guess it is working, but when it detects no signal from the ground Fathom X it turns off.

Any ideas of what tests to run to detect what the source of the failure can be?

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### Author: ![tony-white](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/tony-white/32/13297_2.png) [@tony-white](https://discuss.bluerobotics.com/u/tony-white)
#### Post date: [May 15, 2025, 4:05pm UTC](https://discuss.bluerobotics.com/t/fathom-x-tehter-interface-link-not-working/20380/2 "2025-05-15T16:05:01Z")

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Hi @manci -  
Welcome to the forums!  
Without the link light remaining on, you won’t get a connection via the Fathom-X.  
The best thing to do is verify tether continuity between the two units, and potentially switch to using a different tether pair (3 are unused in a standard 4 twisted pair tether.)

 ![image](https://us1.discourse-cdn.com/flex019/uploads/bluerobotics/original/2X/1/1b3949d428438639c8bde3d7c3a35db7de1cb920.jpeg)  
To switch, you’d have to chage the connection both in the ROV and in the FXTI topside box.

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### Author: ![manci](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@manci](https://discuss.bluerobotics.com/u/manci)
#### Post date: [May 22, 2025, 9:54am UTC](https://discuss.bluerobotics.com/t/fathom-x-tehter-interface-link-not-working/20380/4 "2025-05-22T09:54:52Z")

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Thank you for your comments. After some retrials, the link led and comms work only from time to time. I think it is the USB connector wich does not do a very robust connection. I am tinking of removing the USB connector from the Fathom X Tether interface Board and solderind the USB wires directly to avoid contat issues. USB connectors are not a very robust solution

Best regards