I'm with Ed. At the very least use two different cables for transmit and receive. CAT5 or 6 is not needed. The two pair shielded is the best, especially for long runs. Getting rid of all those failure points (connections) is probably what will fix it.

If you must use your 25 pair use a low count for one side and a high count for the other to keep the trans and rec apart.


Retired phone dude