Hi Jacob! Firstly, thank you for the help.
So I try what you said :
.**each connection is secure on the [Fathom X boards]in the ROV and the [FXTI topside interface box] Re-seat and tighten the wires in the screw terminal blocks : ** done✔
. ** make sure the USB power supply is powerful enough for the FXTI topside interface box. Try using another USB port or a powered USB hub.** : The FXTI is only powered by my laptop, how should I power it with another USB power supply??
.** Try to replace the tether conductors with a pair of shorter wires - to see if the problem is in the tether cable/conductors or the interface boards. Connect the interface boards directly with some pair of shorter wires screwed into the green terminal blocks.** done
.The power and link lights on both interface boards should be illuminated when they are connected correctly - are they illuminated on your board when the tether is connected? What about with a shorter cable?
When I use a pair of shorter wires, the lights (link & pwr) are illuminated on both Fathom X.
But when I use the tether, there is only the Pwr that is illuminated.
So the problem come from the tether ???