The CM-TB8 is a powerful and highly flexible standalone communications unit allowing multiple 4-wire and IFB connections in a 1U rack space. It offers easy connection to any industry standard intercom system, including the Sonifex CM-TLL line listen unit and CM-CU1 and CM-CU21 commentator units.

The 8-channel CM-TB8 intercom control unit is ideal in an OB truck or small studio. The CM-TB8 is an intercom control unit providing 8 channels of 4-wire communication, housed in a 1U rack case.

The unit has individual connections for a headset on 5-pin XLR and microphone/headphones on XLR/stereo TRS jack, with the current selection indicated on the front panel. The gain setting for each input type can be individually adjusted between +6dB and +68dB allowing for a wide range of microphone types, and +48V phantom power is also available. Minor adjustments to the talkback level can be made quickly, using the front panel rotary control with a maximum adjustment range of ±12dB. This adjustment can be disabled if required to prevent accidental changes. A level limiter automatically adjusts the microphone gain if the signal level exceeds a preset level, and the current talkback level is indicated on the front panel when it exceeds 0dB and +8dB. A separate output on the rear panel provides a balanced microphone signal, with adjusted gain and limited level on 3-pin XLR.

Each channel can be configured for 4-wire or interruptible foldback (IFB) operation. In 4-wire mode, the 4-wire input signal is routed to the monitoring channel (headphones/headset and loudspeaker) at the level set by the monitor level potentiometer. When the TALK button is pressed, the microphone signal is routed to the rear panel intercom output connector, and the level to the loudspeaker is reduced to the level preset by the dim potentiometer.

In IFB mode, either the channel's own 4-wire input, or one of two external IFB inputs, is routed to the intercom output connector and can be selected as the interruptible signal. It is also possible to configure each channel so that the input signal is mixed with the microphone input rather than being interrupted by it.

When a channel's TALK button is active, the level of the signal routed to the loudspeaker is automatically reduced by a preset amount, which varies between full power and off. The TALK button also serves as a call indicator. When the signal level on an inactive channel's 4-wire input is above -12dB, the talk button illuminates green. The TALK and GROUP TALK buttons all have a momentary action which automatically latches if they are briefly pressed.

The group talk function allows a pre-selected group of channels to be activated simultaneously. The buttons of all activated channels are illuminated along with the GROUP TALK button. Each channel can be included in or excluded from the group talk function, and by default, all channels are included.

Each channel has a separate monitor level control which sets the level of the signal mixed with other active channels. This signal is then sent to the loudspeaker and headphone monitoring channels and its overall level is controlled by the monitor level potentiometer. The loudspeaker has front panel mute and dim level controls. An external loudspeaker connection on the rear panel provides a level adjusted output and when this output is used, the signal to the internal loudspeaker is muted.

The unit has a built-in line tone generator for easy channel identification and cable checks. The test tone generator has 2 modes. In manual mode, the tone is routed to a channel when the corresponding TALK button is pressed. In auto mode, a tone burst is generated on each channel to uniquely identify it.

A rear panel mounted remote output connector provides tally indication of active talk channels and group talk status via open collector outputs. Other tally outputs indicate the status of the loudspeaker dim and mute controls and also if any of the audio activated call indications are active.

A separate remote input connector provides additional call indication on each channel. When an input is activated, the corresponding talk button flashes. Inputs to remotely control the loudspeaker dim and mute controls are also available.

An optional factory fitted telephony card (order CM-TB8T or CM-TB8G respectively) allows up to 2 channels to be connected to a telephone or GSM network. This allows the operator and intercom users to communicate with a connected caller and both 4-wire and IFB operating modes are available.

The CM-TB8 offers a wide range of user configurable options and there are 6 configuration templates which allow settings to be stored and recalled later. Two of the configuration sets are read-only and cannot be modified. The other four can be used to store custom settings. This allows the unit to be pre-configured for a range of user scenarios which can be instantly recalled. The unit's Ethernet port allows configuration settings to be modified using the built-in web server and an onboard configuration mode allows several configuration options to be modified without requiring a PC.

The CM-TB8 intercom control unit is powered from a universal mains input between 85-264V AC at 47-63Hz.


Features of the CM-TB8 8 Channel Intercom Control Unit

- 8 channel intercom control unit in 1U rack format.
- Separate microphone and headset inputs with phantom power and individual gain settings.
- Microphone talkback level can be instantly adjusted or preset.
- Talkback level LEDs and built-in limiter.
- Configurable 'Group Talk' function.
- Interruptible foldback and straight 4-wire operation selectable on each channel with optional mic-intercom mixing function.
- 2 external IFB (interruptible foldback) inputs available for each channel.
- Optional telephone hybrid or GSM ports allowing direct connection to a telephone line for remote communications.
- Individual monitor level control for each channel.
- Microphone output with adjusted gain and limited level.
- Ethernet connection for remote configuration with built-in web server.
- 6 stored configuration templates with 4 user modifiable sets.
- Front panel loudspeaker with separate output for external loudspeaker.
- Loudspeaker mute and dim controls, also available on remote input.
- Remote tally outputs indicating when each channel is active.
- Remote inputs providing call indication on each channel.
- Built-in tone generator for channel identification.