ASCOM Ascotel 2025, Системное руководство

Страница: 870 / 1141

ascom Ascotel 2025/2045/2065
HBT_20321104_04/B0_en Cabling Interfaces 4.99
7.5.5.4 Connecting a Loudspeaker System
The loudspeaker system is connected via a line input (e.g. audio input for adver-
tising texts) or a microphone input. The input should have a priority circuit and a
separate volume control. The priority circuit is used to fade out the background
music when an announcement is being made.
[1] Jumper for asymmetric input
R
1
, R
2
, R
3
voltage divider when using a microphone input
Fig. 4.70: Schematic diagram of the connection variant for a loudspeaker system
1. When using a microphone input on the loudspeaker system:
– Since microphone inputs are usually designed for low signal levels only, use
a voltage divider to reduce the signal from the door intercom interface (R
1
,
R
2
, R
3
).
– Use a screened cable for the microphone wires for the connection between
the PBX and the loudspeaker system.
– Connect the cable screening to the loudspeaker system only, not to the
PBX or else ground loop humming will occur.
2. Connect the loudspeaker system input to Ta and Tb.
3. Connect the priority circuit to TS and TS’.
Note:
Make sure there are no loudspeakers in the vicinity of the terminals used
to make announcements (to prevent acoustic feedback).
R
1
330
Ta
Tb
TS
TS'
R
2
330
R
3
10
[1]
Loudspeaker system
Microphone input (Pin 3)
1
4
2
5
3
haz1156aaenb0