In 605 A.R. the strangelight workshop developed the first Aural Transponder, dubbed Alpha models. An Aural Transponder is able to transmit and recieve sounds along fiber conduit cable. The device, however, is incapble of transmitting speach and so is limited to a series of sounds (short beep, long beep, sizzle, blop). It became a problem that anyone with a recieving box could tap into the conduit and listen in on messages. That spurred the development of the Beta model which utilized rune plates sets so that only one runeplate could communicate with another.
The transmitter unit appears to be a series of piano keys attached to a glowing box of red liquid. The sending fiber conduit cable has four wires which are unwound and stretched through the liquid.
The reciever unit is simply a glass box of the same red liquid with a round horn fastned to the top wall from which the recieved sound escapes.