I'm looking for a C1607/4 control box. This is for a Plessey PTR-175 UHF transceiver. This is a variation of the ARC-52 that has a VHF range added. The /4 is what makes the difference. The first digit on this control box can be set to 1, 2 and 3 where the normal C1607 ARC-52 control box only does 2 and 3.