I nned some detailed technical info regarding the way that partyline comms systems are configured. For example, what each pin on the cable carries, how signals are input to the system etc. The project is to basicly create a wireless system which can be added to an existing system using the componants from standard FRS radios to carry the signals. This is a project for my own benefit, so no biggie if it doesnt work. I have worked out how to make the wireless stuff work, now I just need to know how to interface with another system. I figure, for 4 beltpacks, I will need 13 radios (4 transmitters in the packs, 4 recievers in the packs, 4 recievers at the base and 1 transmitter at the base) and 5 radio frequencies will be needed. Thanks in advance, Tom By the way, I am on holidays in Vietnam so I may not be able to reply immediatly to posts.