Both intercom circuits have their own individual power supply with short-circuit protection. All protection is electronic and automatic and no resetting is necessary following removal of a fault condition. As the supplies are independent, in the event of a cable fault temporarily disabling one circuit, the other circuit will continue to operate uninterrupted. The Master Station can be operated world-wide without the need to change power supply settings.
Each intercom circuit (A and B) can power up to 22 Tecpro BP511 beltpacks, or a mix of various headset and loudspeaker stations. Circuit B may be linked to circuit A to form a single circuit.
The operator listens and talks to other users on the intercom system by plugging a headset into the 4-pin XLR connector on the front panel. Two sidetone presets, accessible through the front panel, allow the operator to set the level of his/her own voice in relation to the voices of other users on the system. A low level headphone alert in the form of a short ‘beep’ is heard when any function switch is depressed or if any outstation calls. This function can be turned off via an internal link if it is not required.
The operator may speak to circuit A, B, or both by pressing the associated circuit select buttons. Both circuits remain independent and cannot communicate with each other (unless linked).
To attract the attention of operators who have removed their headsets, all beltpacks and most loudspeaker stations are fitted with call-lights. Depressing the ‘Call A’ or ‘Call B’ switch triggers all call-lights on that circuit to illuminate.
A microphone or line level auxiliary signal can be added to Circuit A or B, both or none by pressing the Aux button and toggling through the four options. This allows external sources such as programme feeds, show relay or paging announcements to be mixed on to the intercom circuits. The amount of auxiliary signal added is set using the ‘Aux Level’ control.
Series 2 Tecpro beltpack and user stations operating on circuit A or B can have their microphones switched off remotely from the MS745 Master Station by use of the ‘Remote Mic Kill’ or ‘RMK’ facility. This avoids the build up of unwanted background noise caused by microphone circuits being open unnecessarily. It should be noted that original style Tecpro beltpacks and user stations have mechanical mic ON/OFF switches rather than the electronic type used on Series 2 devices and are unable to respond to ‘Remote Mic Kill’.