Sonifex CM-TB8 Talkback Control Unit

CM-TB8 Talkback Control Unit - (8 Channels of 4 Wire Comms)

The CM-TB8 is a powerful and highly flexible self contained communications unit allowing multiple 4-wires and IFBs within a single 1U rack space. It offers easy connection to any industry standard talkback system including the Sonifex CM-TLL line listen unit plus the CM-CU1 and CM-CU21 commentator units.

The CM-TB8 8 Channel Talkback Control Unit is ideal in an OB truck or small studio. The CM-TB8 is a talkback control unit providing 8 channels of 4-wire communication, housed in a 1U rack mount enclosure.

The unit has individual connections for both 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 set between +6dB and +68dB allowing for a wide range of microphone types and +48V phantom power is also available. Small talk level adjustments 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 stop inadvertent changes. A level limiter automatically adjusts the microphone gain if the signal level exceeds a preset level, and the current talk level is indicated on the front panel when it exceeds 0dB and +8dB. A separate output on the rear panel provides a balanced, gain adjusted and level limited microphone signal on 3 pin XLR.

Each channel can be set to either 4-Wire or Interruptible Foldback operation. In 4-Wire mode the 4-Wire input signal is routed to the monitor channel (headphones/headset & 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 talkback output connector, and the level of the feed to the loudspeaker is reduced to the level preset by the dim potentiometer.

When in IFB mode, the channel’s own 4-Wire input, or one of two external IFB inputs, is routed to the talkback 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 ranges between full on and off. The TALK button also acts as a call indicator. When the signal level on the 4-Wire input of an inactive channel is above -12dB, the talk button illuminates green. The TALK and GROUP TALK buttons all have a momentary action that will automatically latch on if they are briefly pressed.

The group talk function allows a group of preselected channels to be activated simultaneously. The buttons on all activated channels are illuminated as is the GROUP TALK button. Each channel can be included or excluded from 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 that is mixed with the other active channels. This signal is then fed to both the loudspeaker and headphone monitor channels and its overall level is controlled by the monitor level potentiometer. The loudspeaker has front panel mute and dim attenuation 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 speaker is muted.

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

A factory fitted optional 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 the talkback users to communicate with a connected caller and both 4-wire and IFB operation is available.

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The Company agrees to repair or (at its discretion) replace Goods which are found to be defective (fair wear and tear excepted) and which are returned to the Company within the Warranty Term provided that each of the following are satisfied:

1. (i) notification of any defect is given to the Company immediately upon its becoming apparent to the Purchaser;
2. (ii) the Goods have only been operated under normal operating conditions and have only been subject to normal use (and in particular the Goods must have been correctly connected and must not have been subject to high voltage or to ionising radiation and must not have been used contrary to the Company's technical recommendations);
3. (iii) the Goods are returned to the Company's premises at the Purchaser's expense;
4. (iv) any Goods or parts of Goods replaced shall become the property of the Company;
5. (v) no work whatsoever (other than normal and proper maintenance) has been carried out to the Goods or any part of the Goods without the Company's prior written consent;
6. (vi) the defect has not arisen from a design made, furnished or specified by the Purchaser;
7. (vii) the Goods have been assembled or incorporated into other goods only in accordance with any instructions issued by the Company;
8. (viii) the defect has not arisen from a design modified by the Purchaser;
9. (ix) the defect has not arisen from an item manufactured by a person other than the Company. In respect of any item manufactured by a person other than the Company, the Purchaser shall only be entitled to the benefit of any warranty or guarantee provided by such manufacturer to the Company.