Thank you again Norm.
The total cable length is about 150’.
Wireless is not an option due to the fact that the remote module (slave) will, at some point, be submerged and a 100 % reliable connection is a must.
The cable you suggested fits some of the requirements but I’m looking for only one twisted pair and two power wires. Heavy duty jacket and shielding are a must along with availability in large quantities with no lead time. I will be employing half duplex communication using a custom protocol.

I can not express enough how much I appreciate your help.

I might have to contact some of the major cable manufacturers for some help but I tried the forum first hopping that someone might already be using something like this and knowing that is nothing I can do until after the weekend.

Regards,

Nick