Wiring Audio Taps; Balanced Signals - Vidicode APRESA Series Installation Manual

5.4.

Wiring audio TAPs

The interface-card that is used to make an AUDIO tap is the ATP-card. See chapter 13.1 for the
specification and the connections of this type of interface card. This is also
the wiring method for (mobile) communication transceivers used by police
etc. These radios must have an audio output for the mixed
microphone/speaker signal.
For the pin assignment of the RJ21connector on the interface card see
the figure on the right. Every channel needs 2 wires CH-x-A and CH-x-B.
5.4.1.
It is preferred to feed balanced pairs to the interface card. This will give
the best results in terms of hum and other distortion. Every analog input of
the APRESA is built with individual line transformers and DC blocking
capacitors, in a truly balanced configuration.
AUDIO AUDIO
SOURCE SOURCE
BALANCED
PAIR
The interface card will not provide any realistic line termination, so if the audio line is not terminated by
other equipment (typically an amplifier) you probably want to add a line terminator in some situations. If
you want, f.i. 600 ohms line termination you have to provide the 600 ohm termination resistor externally.
AUDIO AUDIO
SOURCE SOURCE
BALANCED
PAIR
INSTALLATION MANUAL APRESA

Balanced signals

CHx-A TO
APRESA
CHx-B
LINE
term ination
COPYRIGHT © 2011-2017 VIDICODE ®
AM PLIFIER AM PLIFIER
SPEAKER
DWG1136_00
CHx-A
TO
APRESA
CHx-B
DWG1136_00
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