Ampcontrol VAA, User Manual

Page: 60 / 81

VOICECOM USER MANUAL ISSUE 4
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Figure 45 - VAA Addressing Single Line
4. Once all the VAAs have been correctly addressed, a block
symbol for each VAA will appear on the Line Status page
for that line. If two VAAs have been given the same
address a C symbol will appear at the address where the
clash exists. Re-check the addressing if necessary.
5. Ensure that all the VAAs are online.
Volume, Microphone Gain and Audio Threshold
The procedure for configuring these settings can be found in the VCA Operation chapter, under the section VAA
User Programmable Settings. These settings can also be adjusted at the VAA. The procedure for changing settings
at the VAA can be found in the VAA Operation chapter, under the section VAA Setup Mode.
The default settings should be adequate. These are:

Volume: 3 (maximum)
Volume level 3 may be too loud for certain locations.

Mic Gain: H (high)
The microphone gain should be set to L (low) in areas with a high level of background noise.

Audio Threshold: 2
It is possible that noise from other electrical and electronic systems could be picked up by the VAAs.
Depending on the level of this interference, the VAA may amplify the noise. If this noise is amplified for
extended periods, the VAA battery charge can become depleted, causing the battery to shut down.
Increasing the audio threshold will prevent the VAA from unnecessarily amplifying any noise. Note, however,
if the threshold is set to high, legitimate audio from other operators may get cut off.
These settings can also be adjusted at the VAA. The procedure for changing settings at the VAA can be found in the
VAA Operation chapter, under the section VAA Setup Mode.
Some testing may have to be done to find the most suitable settings for the particular installation.
Charging Current
The procedure for setting the VAA charging current is the same as setting the volume, mic gain and threshold. The
default charging current is:

Charging current: 30mA
For installations with many VAAs connected over a longer distance, this value may have to be lowered. The amount
of charging current available largely depends on output of the power supply. As an example, consider the following
installation:
CALL
LOCAL
CALL
EXCHANGE FUNC. SPEAK
VAA Field Unit
+ -
CALL
LOCAL
CALL
EXCHANGE FUNC. SPEAK
VAA Field Unit
+ -
CALL
LOCAL
CALL
EXCHANGE FUNC. SPEAK
VAA Field Unit
+ -
CALL
LOCAL
CALL
EXCHANGE FUNC. SPEAK
VAA Field Unit
+ -
CALL
LOCAL
CALL
EXCHANGE FUNC. SPEAK
VAA Field Unit
+ -
CALL
LOCAL
CALL
EXCHANGE FUNC. SPEAK
VAA Field Unit
+ -
LINE 1
Adr
15
Adr
14
Adr
1
Adr
16
Adr
17
Adr
31
2 Line 1 [20] VAA’s
PSW RQo/o OPo/o
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