A commonly asked question is one dealing with callsignal on the “A” channel of the RS-603.
The RS-603 two channel beltpacks require a TWC-701 interface in order toconnect to a standard Clear-Com partyline system.
The TWC-701 is a  2-channel/3-pin XLR  adapter module; it combinestwo standard intercom channels onto one single 3-pin cable for beltpacks withthe TW option and is necessary for the beltpack to operate in two channel mode,as it is the only way to combine the two channels on one 3pin XLR.
It will also only pass one call signal from the Clear-Com mainstationside of the interface to the RS-603 beltpacks. However between two RS-603 units, the beltpacks will have two call signals. The RS-603 default to receive standard Clear-Com call signal their ChnlB In order to have the beltpacks have channel “A” call amongst themselves,you will  need to use the V-PAK software availablefrom our website      http://www.clearcom.com/support/partyline-software to program the RS-603 beltpacks to allow AC signaling on channel“A”. You’ll also need to make a cable from a DB=9 female to3.5mmTRS   using D-sub’s pins 2, 3 and 5 to TRS respectively.
Alternatively you can purchase the Vpack including the programming cablefrom Clear-Com