A range of intercoms aimed at broadcast applications, which will work together to form a talkback system, will integrate with many other existing systems. Free-standing and rack-mounting models are offered, with integrated speakers and microphone. Each has the capability to talk to other locations, monitor external inputs and has flexible configuration capability.
TB-6D Talkback Intercom
Desktop units to communicate with up to six other locations. On the top panel there are six buttons for talkback selection and two for external inputs. A volume control adjusts the levels of both speaker and headphones. While a button is pressed, the button is illuminated and the talkback signal is active to that location. The buttons work with both a momentary and latched operation. If held down, the selection is cancelled when released, otherwise the button is alternate action. When talkback is incoming, the external inputs can be either muted or mixed with the incoming signal, depending on the setting of an internal jumper.
The signal sent to the other locations can be from the onboard electret microphone on the front panel or a separate external microphone signal. Incoming signals can be monitored using the loudspeaker or headphones . When the headphones are used, the speaker is automatically muted, or, the monitor speaker can be muted via a remote contact. Two external sources may be monitored for example, for confidence monitoring, or for listening to a station feed. The top of the case also has the loudspeaker grille and an XLR for the external microphone connection.
On the rear is an associated preset gain control, a switch to select microphone source, the 6.35mm stereo headphone socket, two stereo, balanced external inputs via a 9-pin D-sub connector which also carries remote control signals, two RCA (phono) sockets for external input 2, and a preset level control for the incoming talkback signal. In addition there is an IEC power inlet, fuse and the 15-pin D-sub connector to connect talkback input and outputs to the other locations.
Internal jumpers can be configured to use alternative sources rather than the onboard microphone amplifier and to feed the monitor signal to other systems such as a mixer, rather than the internal monitor amplifier. The intercom is then used for switching and monitoring external inputs.
The TB-6D/R intercoms use ‘phantom’ or ‘common-mode’ DC signalling, where a ground is placed on the centre-tap of a transformer, to communicate, so are compatible with many of the other talkback systems in use. A sending station places an earth on the centre-tap; this is detected by the receiving unit, which then un-mutes (and provides a DC signal to dim local monitors if required). Each station has a single listen line input and six outputs. When any of the talk buttons is pressed, outgoing talkback and signalling is sent to the selected line. The ‘send’ circuits to a single receiving unit are simply connected in parallel to the input of the receiving unit. Since sending impedance is quite high, and receiving input is quite low, the effect is to mix any incoming talkback signals.
TB-6R Talkback Intercom
Housed in a 2U rack-mounting case, this is similar to the TD-6D. The external microphone input XLR is on the front panel, as is the speaker grille.
||External inputs; greater than 30kohms unbalanced, 40kohms balanced
||Microphone; 74dB to 53dB
||Talkback; 9dB to -28dB
||150mW into 32-600ohms
||Headphone output; 9dB to bellow-60dB (off)
||85V - 264V AC, 47-63Hz
||Desk units; 60 x 86 x 224 x 225 mm (h-front x h-rear x w x d)
||Rack mounted units; 89(2U) x 483 x 185 (h x w x d)
||Desk units; 1.25kg. rack mounted units; 2.6kg
Included accessories: Manual and IEC power cordset.
Optional accessories: Gooseneck microphone. See Canford dynamic gooseneck microphones.