KB-701
The KB-701 remote speaker station connects to a single channel of partyline intercom, and operates in half-duplex mode, similar to a walkie-talkie.

KB-702
The KB-702 remote speaker station permits the user to select between two channels of partyline communications, with the ability to talk and/or listen on the selected channel.

KB-702GM
The KB-702GM remote speaker station permits the user to select between two channels of partyline communications, with the ability to talk and/or listen on the selected channel, like the KB-702 but adds a gooseneck mic connector and VOX circuitry.