Telex 38109-977 manual IFB System One Way Communications System, How an IFB Works

output of a Master Station or User Station with a “Hot Mic” output. The IFB electronics receives its program audio from the audio mixer board.

The IFB System (One Way Communications System)

IFB is a television acronym for Interrupted FeedBack, Interrupted FoldBack, Interrupted Return Feed (IRF). An IFB system permits a director or producer to talk to the talent, typically an “on air” announcer, newscaster, or sportscaster. Normally the talent hears the broadcast program audio. When the director or producer activates the IFB, the program audio is replaced by the director’s or producer’s voice. Sometimes the program audio continues in the other ear, sometimes the program audio is reduced instead of completely removed.

How an IFB Works

Those in control positions (the director, producer, or assistant director for example) control the interrupt and or announce functions via control stations. Those in receive positions (on-air talent, floor managers, studio or field crew, audience, talent and crew in remote locations) are on the receiving end of the user station feed or on the actual user stations (talent electronics or talent station) via headphones, headsets, earphones, and / or loudspeakers. In the middle, the central electronics unit provides all the necessary inputs and outputs, processing, switching, and power distribution.

Studio and Some Field Applications

Note Model numbers of the different parts of the IFB are as follows:

Control Panel

Audiocom®: Built into US2002, ES4000A. Clear-Com: MA-4, AX-4. RTS™ TW: Models 4001, 4002, 4003

IFB Electronics

Audiocom®: Built into US2002, ES4000A; Clear-Com: PIC4000B; RTS™ TW: Model 4010

Talent Receiver

Audiocom®: IFB1000; Clear-Com: TR-50; RTS™ TW: Model 4030

Earset

Audiocom: CES-1; Clear-Com: (part of Model TR50); RTS™ TW: CES-1

In non-sports activities, the talent normally uses only the interrupt output (mono) of a Talent User Station. The earphone is hidden behind the talent’s back; a plastic tube runs from the earphone to the talent’s ear.

Field Application, Sports

In the sports broadcasting or sports communication field, the talent uses a noise resistant headset. The microphone on the headset is the “air” microphone; the headphone is double muff, stereo. The talent is plugged into the stereo output of (for example) the Model 4030 Talent Receiver User Station. At the IFB Control Station, each talent’s name is marked on a strip of tape pasted adjacent to the push buttons.

In stadium sports, there is usually little problem in getting a microphone cable from the IFB Electronics to the Talent Receiver. In the case of golf, auto racing, and sports venues over an extended area, the distances may be too great. In this case, a four wire circuit can be run to the talent location and adapted to the connector on the Talent Receiver.

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