Telex 38109-977 manual Connecting Interfacing to Other Communications Systems

In some more extreme cases, only a single pair of wires may be available. In this case, plug the talent’s stereo headset into the stereo connection on the talent receiver, then connect the high side of the pair to pins 2 and 3 of the XLR3 connector and the low side to pin 1 (pseudo-stereo mode). This will give a mono feed with each ear individually adjustable and both ears interrupted.

For runs of two miles of number 22 gage twisted pair, at least one talent receiver station should be operable. For a run of one mile, two talent stations should be operable.

Some users have increased the number of talent stations by using higher impedance (300 ohms) headsets. In the case of auto racing and similar loud environment situations, low impedance noise isolating headsets will be necessary to overcome the volume and amount of sound. It may be necessary to use a four wire circuit to connect up each talent station, paralleling the pairs, and running the talent receiver in pseudo-stereo mode, using only the interrupt (“wet”) output of the IFB electronics.

Field Application, ENG (Electronic News Gathering)

In this case, the earphone is again hidden as in the studio case above. If the talent has to carry on a conversation with other talent at the studio and other venues, the program feed should be a mix minus feed. The mix minus feed will allow the talent to hear the other talents loud enough without hearing their own self too loud.

Connecting (Interfacing) to Other Communications Systems

What is interfacing? Interfacing is either:

1The interconnection of two normally separate communications systems into one system.

-OR-

2The connection of a communications station or device that is not directly compatible within a system.

To accomplish this, voice and data information is adjusted and then transmitted to the other system. The adjustments include level translation, impedance compensation, mode translation, and compensation for parameters of each system.

Some examples are:

1System to system: connection of a four-wire matrix system installed on a large mobile unit to two-wire belt packs outside of the mobile unit.

2System to terminal: connection of a camera with a built-in intercom to an intercom system, or connection of a radio transceiver into an intercom system.

Why is there interfacing, operationally? From an operations point of view:

1An operation requires a larger collection of personnel and equipment than normal.

2A mobile unit is used with a permanent installation to conduct an operation.

3Coordination between personnel / equipment is required at a remote location.

4A special part of the operation requires communication with an odd system or terminal.

5A redundant “backup” path is required.

Why is there interfacing, technically? There are system to system, system to terminal or, system to device differences.

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