Clear-Com’s TW-12B intercom system interface is designed for connecting one intercom system to another, without compromising the audio quality of either system. The TW-12B solves all problems that can arise when connecting, for example:
- a mobile production unit’s intercom system to an intercom in a nearby building
- same-type systems located in two different buildings
- to any “unknown” interface, such as a TV camera
- concert hall’s intercom to touring group’s intercom
Transparent Isolation Between Systems
The unique TW-12B completely eliminates hums and buzzes caused by ground loops (which occur when you interface two systems that use different power supplies or grounds). The TW-12B compensates not only for level differences between systems, but for varying impedances caused by transformers and capacitance on the lines.
The completely transparent TW-12B provides an electrically isolated interface between the two intercom systems. Either “side” of the interface can connect to a Clear-Com intercom system or an RTS intercom system, allowing Clear-Com-to-Clear-Com, Clear-Com-to-RTS, and RTS-to-RTS combinations. In addition, the TW-12B passes through and translates “call” signals, Clear-Com-to-RTS and vice versa.
The interface consists of two identical, 2-wire-to-4-wire hybrid networks which break the ground loops that occur when two systems are run from separate power sources. The audio paths are transformer-coupled, and the signaling circuits areopto-isolated.
Fast, Easy, and Accurate Setup
The operator can quickly set up the TW-12B by using a standard intercom headset and the TW-12B’s built-in setup tone. The TW-12B is capable of a range of null adjustments, allowing it to adapt to a wide variety of line conditions, line lengths, and impedances.
Clear-Com’s innovative, nulling system provides up to 40 dB null. The TW-12Bprovides each side of the system with null adjustment controls that allow adjustment even when the system is operating.
The rear panel of the TW-12B contains a pair of 3-pin XLR connectors (one male, one female) for each side of the interface.
Call Signal Translation
The TW-12B interface receives "Call" signaling in the appropriate form (DC level for Clear-Com, tone for RTS,) decodes it, and passes it to the other side of the interface, via an optical coupler. The receiving side of the interface sends the signal appropriate for the connected intercom.
Gain
A recessed Send Gain control allows an adjustment of +/- 6 dB for each side of the interface if necessary.
Power
Each side of the TW-12B is powered directly by the intercom system to which it is connected. The unit draws about the same amount of power as a belt-pack. If either system is disconnected, the power loss immediately shuts down the associated electronics, eliminating any unwanted noises on the operating intercom side. The TW-12B front panel provides an LED power indicator for each side of the interface.
