Telex 38109-977 Intercom System User Manual


 
32 Handbook of Intercom Systems Engineering
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.