ZETRON 4000 Series, Installation Manual

Page: 183 / 418

183
Dual Channel Card Audio Levels

To adjust receive audio levels for conventional radios
1. Ensure that gain settings throughout the Series 4000 system are configured for
their default settings. See
Before Adjusting Levels
on page 182.
2. With the base station connected to the channel card use a communications service
monitor to send a 1000 Hz sine wave at 40% radio channel deviation to the base
station.
3. Connect an AC voltmeter at the channel card “AGC” test point on the card edge.
Warning! This adjustment procedure only works if VOX input is
connected to the AGC output.
•
If your firmware version is prior to 2.70
, VOX is always
connected to the AGC output. Use this procedure.
• If your firmware version is 2.70 , VOX is always
connected to the AGC input. In this case you must use a
different procedure. See
Setting Rx Levels for Dual Channel
Cards (VOX input connected to AGC input) on page 190.
• If your firmware version is 2.74 or later , the VOX/AGC
connection is user-configurable. The typical and default
setting is for VOX input to be connected to the AGC output,
in which case you can use this adjustment procedure. If you
have changed this setting, you must use a different
procedure instead. See Setting Rx Levels for Dual Channel
Cards (VOX input connected to AGC input)
on page 190.
To check the firmware version and to check or change how
VOX is configured:
1. Connect a PC serial port to the dual channel card's front
panel "MONITOR" jack using a Zetron cable part number
709-7452.
2. Using Hyper-Terminal (or equivalent) as a terminal emulator
set the communications parameters to 19200-8-N-1-NONE.
3. Press <ESC>? To display the channel card's current
configuration & version.
Note The receive audio adjustment process could also be performed if
the user were to inject an audio signal at 0dBm or 2.2V (Peak to
Peak) on the RX- / RX+ pin pair at the punch down block with all
equipment connected.
Tip When adjusting Wireless Dual Channel Control Cards such as the
MAP27 Dual Channel Control Card, the installer can transmit the
console's generated alert tone to the connected radio or a Model
427 channel that is being aligned, and use the alert tone as its
receive audio.
STOP