Sony camera ILCE-7M2 (USB) to Ethernet through Fathom-X


I was not sure if the question should be place into “build” category or “product support”, my apologies for the convenience.

I would like to have more information about the usage of Fathom-X and maybe Fathom-S.

I try to add an independent Sony camera (ILCE-7M2, with enclosure) to the existing system (BlueROV2 + accessories) in order to take better picture and use our camera equipment.

We have done a working build with USB/RJ45 (V.TOP NT50 - This build implies an extra Ethernet cable with a limit size of 30m. We retrieve the video and we are able to take pictures which stores into the SD card. The video and the command is done thanks to Sony application on a computer. See image below :

After that, we have try to done the same system without the extra Ethernet cable and go through a Fathom-X and a Tether cable. See image below :

We have used 2 kind of device for USB/RJ45

  • one cheapest USB/RJ45, D+/D- directly sent to pin 1/2 ethernet
  • one more sophisticated (with ASIX) but not working (only one twisted pair)

The following picture show the whole end system (the red path correspond to the test path and the previous image) :

I encounter some troubles with the add of the Fathom-X to the system.

My Questions :

  1. I would like to Know if the Fathom-X fits our needs. Would it be better to use a Fathom-S to link directly USB communication through Tether cable ?

  2. We have seen that the Fathom-X used 2 twisted pairs for the Ethernet connector (100BASE-T2 ?), otherwise the USB/RJ45 in our possession used only one (100BASE-T1). Is there a specific USB/RJ45 converter to use ? Moreover the Fathom-X Topside Interface (FXTI) contains a USB to Ethernet converter. Do you have a reference ?

See image below of Fathom-X routing (RD-/RD+ et TD-/TD+).

Any help would be appreciated.



Hi @Schade,

Thanks for the post and details! The Fathom-X can handle additional Ethernet connections through a switch but they must communicate using proper Ethernet signals. Passing D+/D- from the USB into the Ethernet port will not work.

The USB/RJ45 extenders you linked are not compatible Ethernet devices so they cannot be connected to the switch.

How does the Sony camera output its video? You will likely need an HDMI to IP (Ethernet) adapter or connect this in another way. If it’s just a USB camera then it might be possible to connect it to the Raspberry Pi but we don’t yet have support for multiple cameras in there.


Hi Rusty,

Thanks for your rapid answer !

I was wondering about that. Please find below the image of the output specification of the camera.

I want to be able to take picture at the good moment, the video will help us to trigger the shot. It’s why we want to used the USB connection with a PC as a remote.

Do you have a reference for USB/Ethernet (compatible with Fathom-X, 2 twisted pairs) ? Do you use a similar device into the Fathom-X Topside Interface (FXTI) ?

If I used a HDMI to IP adapter, I will lost the remote possibility ? and just retrieve the video ?

One picture of the device :

Thx Rusty,

Are you using a sony application to connect to the camera by usb? If so, and you hope to get video and camera control with sony’s application through the usb port of the camera, you will need to find something to extend the usb signal itself for the length of the tether. The fathom x will not work for this, and I haven’t seen anything myself that will help you here.

Hi @Schade, thanks for the info.

I think you will need an HDMI to IP adapter connected to the Fathom-X via an Ethernet switch to do this. Alternatively, you can use a third Fathom-X board connected to the same wires instead of an Ethernet switch.

Like Jacob mentioned, if the USB control is through a Sony application, it might be necessary to find an alternative.


For the moment we are investigate with the Sony application through USB but we are open to others solutions.

Is there specific USB to ethernet through Fathom-X or maybe usefull references ?

Thanks for your advices we are going to test with another USB to Ethernet device and looking for another way to achieve our goal.

Our first attempt was to used the Sony application.

I will be back with more information.

USB to ethernet converters are not what you want. The search term should be something like ‘usb extender’. I am not aware of any solutions for you.

Ok, stop me if i ma wrong but the principles of an extender is to amplify voltage signal in order to sent it through long distance ?

Is this amplification matching with the voltage level required with the Phatom-x ? I will take deeper look with USB extender but I think we have to find another way to achieve it.


Different communication extenders work different ways, it doesn’t necessarily have to involve a voltage increase.

The fathom x and ethernet will not be useful for you if you are using a sony application over usb.

Our first successful test was done with an USB to Ethernet Extender but with an extra Ethernet cable attached to the Tether cable.
We have thinks to used the Fathom-x in order to remove the extra-cable.

Is it possible to used the Tether cable differential pair directly with the USB extender ? (I haven’t check the impedance of the differential pair of the Tether cable) ?

Hi @Schade,

Did you had more progress in this? I am trying to do the same but without success, the USB to Ethernet Extender doesn´t provide a real conversion to ethernet, just use the Cat 5 to extend the usb signal.


1 Like

Hi @lbentes,

Not really, I have to ask to my workmate.

From memory, We have change our application. We have used a gopro and retrieved the full video of the trip and select the correct image. It was enought for our application. However, We will be back on this problem in a few time.

We have success to do that only with 50meters extender.