Home        Store        Learn        Blog

Dual Ethernet + Serial + Power MUX Replacement for Fathom X

Some of you have already heard about this and a few have actually seen it, but now we are ready to get it out there and make it available to everyone The DEPS MUX (Dual Ethernet Plus Serial Multiplexer) is a drop in replacement for the Fathom X board in the BlueROV2.
The DEPS MUX was initially designed to allow for 2 Ethernet connections over a single twisted pair on one board but we quickly realized that when adding accessories/devices to the BlueROV2, many will not take the standard power available in the BlueROV2. So we added clean 12VDC & 24VDC power supplies to the DEPS MUX to power accessories like multibeam sonars, cameras, CTDs, etc. It can also replace the 5VDC power regulator in the BlueROV2 with its 5VDC power supply that is “backed-up” with super capacitors and provide clean 5VDC power under heavy loads (battery or surface power).
The DEPS MUX also has a RS232 to RS485 convertor onboard which does require the use of a second twisted pair in the tether and a RS485 to USB convertor topside.
More info…


Hi, can you say anything about the price and shipping date?
Jan R

Nice work Jeff and the Bluelink Team !!

1 Like

Price is $495 for the DEPS MUX but only one board is needed in the ROV as it was designed to be compatible with a Fathom X topside.

Dual power line carrier modules do not provide double bandwidth, sometimes even slower. The crosstalk of 3-56M dual signals on parallel twisted pairs is very serious.

Ethernet is very convenient to add switches, so adding one switch at each end is a better choice.

Because most people already have a FathomX with LX200 interface module at the topside, we use 2 modules subsea (over only a single twisted-pair) on our MUX at the ROV end. It is correct that crosstalk between two set of LX200 modules on two different twisted-pairs would serious, and also that the bandwidth doesn’t double, in fact it will still be limited by the one module on the other end. However, the homeplug standard accommodates more than 2 modules on the same wire (to a limit) and we wanted to run with a proven solution. Bench testing shows 9.6MBytes/second in UDP and around 9.1MBytes/second in TCP/IP total bandwidth using a 300m tether (partially spooled in the lab). Our most realistic (and satisfying) test is operating the BlueROV2 with over 200m of tether in the water using both 1080P/30fps video and Gemini720ik at full resolution simultaneously When we have a calm day and the equipment onboard, we will measure/publish the data with the full 300m tether in the water. There are subtleties to running more than 1 module on each end or a switch + 1 module, and we have preferred the former for both simplicity and redundancy.

There is no problem in performance when using the same pair of twisted pairs, but I think the cost of two PLC modules is more expensive than that of the PLC + switch, and the power consumption will be greater.