Clear-Com TW-12C Encore System Interface

The unique TW-12C completely eliminates hums and buzzes caused by ground loops. The TW-12C compensates not only for level differences between systems, but for varying impedances caused by transformers and capacitance on the lines. The TW-12C 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-12C 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 are opto-isolated.

The operator can quickly set up the TW-12C by using a standard intercom headset and the TW-12C’s built-in setup tone. The TW-12C is capable of a range of null adjustments, allowing it to adapt to a wide variety of line conditions, line lengths, and impedances. The TW-12C provides each side of the system with null adjustment controls that allow adjustment even when the system is operating. The rear panel of the TW-12C contains a pair of 3-pin XLR connectors (one male, one female) for each side of the interface.

The TW-12C 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.

Each side of the TW-12C 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-12C front panel provides an LED power indicator for each side of the interface.

Clear-Com TW-12C Features

• System isolation for: Clear-Com to Clear-Com, Clear-Com to RTS, RTS to RTS
• Eliminates grounding problems between intercom systems
• Matches gains between systems
• Passes through and translates signaling
• Hybrid nulling up to 40 dB
• Built-in setup tone
• Powered directly from connected intercom system

• TW-12C Encore system interface1

• Clear-Com Format
  • Line Characteristics
  • Max Level Before Clipping: >=3dBu
  • Impedance: >=10KΩ
  • Signaling
  • Receive: <=4V DC
  • Send: >=11V DC
• RTS Format
  • Line Characteristics
  • Max Level Before Clipping: >=5dBu
  • Impedance: >=10KΩ
• Frequency Response
  • Partyline – Partyline: 200-8kHz
• Signaling Tone
  • Send frequency: 20kHz ±100Hz
  • Receive frequency: 20kHz ±500Hz
  • Send level: >=-6dBu
  • Receive level: <=-25dBu
• Distortion
  • Partyline – Partyline: <=0.2%
• Max. Gain
  • Clear-Com – RTS: >=9dB
  • Clear-Com – Clear-Com: >=4dB
  • RTS – Clear-Com: >=-1dB
  • RTS – RTS: >=4dB
• Min. Gain
  • Clear-Com – RTS: <=1dB
  • Clear-Com – Clear-Com: <=-4dB
  • RTS – Clear-Com: <=-9dB
• Power Requirements
  • Input Voltage Range: 20-30V DC
  • Input Current (average): <=50mA
• Dimensions (HxWxD)1.75" x 19" x 7.25"
• Weight5.63 pounds