Fathom-S Tether Interface Board Set


The Fathom-S Tether Interface Board Set provides the communication and video signals needed for an ROV. It interfaces with the Fathom tether or any standard Cat5 cable with four twisted pairs of wire. It has the following features:

Through the Tether

  • Low-latency analog video using a differential video amplifier for crisp, colorful video over 300+m of cable. It’s compatible with any camera that has a standard NTSC or PAL video output.
  • Long-distance serial connection using RS-422 differential amplifiers for high-speed, reliable communication over 600+m of cable
  • Power on/off switch allows you to switch power on and off for small electronics. For high power switching, this can interface to a high-current power switching board.

Topside Interface

  • Screw terminals for tether connection
  • RCA video output compatible with any NTSC/PAL display or video capture card
  • USB serial port to easily connect to a computer
  • TTL serial port (5V) for direct interfacing to a computer or microcontroller
  • Power-on is switched on when connected through USB or powered otherwise
  • Jumper for reset-on-RTS to allow Arduino microcontrollers to be programmed through the tether
  • Optional external power input (7-20V)

ROV-side Interface

  • Screw terminals for tether connection
  • Header pin connection for analog camera
  • 12V regulator for the analog camera, accepting up to 20V input
  • TTL serial port (3.3V logic, 5V tolerant) compatible with Arduino, Raspberry Pi, and DroneCode autopilots
  • DroneCode Mini compatible connectors for quick connection to Pixhawk and other DroneCode autopilots
  • 5V regulator to power low-current electronics such as an Arduino
  • Jumper to enable/disable tether power switch

The Fathom-S Tether Interface Board Set is open-source and open-hardware, so the schematics and board files are free to view, modify, and reuse. The electrical schematic and board layout are open-source and the design files are available below.


  • 1 x Topside Interface Board
  • 1 x ROV Interface Board
  • 2 x 2mm jumper

Available on backorder

SKU: FATHOM-S-R1-RP Category:

The Fathom-S boards provide low-latency video, a serial port connection, and remote power on/off switch for tethers of 300+m length. Use with the Fathom tether or a Cat5+ network cable.