ZETRON 4000 Series, Installation Manual

Page: 191 / 418

191
Other Audio Adjustments
6. If necessary, change the VOX setting to -20 dBm on the appropriate channels. The
following substeps briefly describe setting both channels with a delay of 2 seconds
and set to - 20 dBm:
a. Set channel A. From the main menu type:
<ESC> C A D C D D C T B
<BACKSPACE> S
b. Set channel B. From the main menu type:
<ESC> C B D C D D C T B
<BACKSPACE> S
c. Press
<ESC> ?
to display the channel card’s current configuration.
d. Confirm the channels were configured correctly with a VOX level of - 20 dBm.
(Look for “...VOX_input, -20 dBm”.)
For help with navigating these menus, see Navigation on page 55. For more detailed
instructions regarding the VOX setting, see
To define the channel’s Call input
source on page 57.

To adjust the Rx audio level
1. Turn both the 4W Rx and the 2W Rx pot all the way down (fully counter-
clockwise, 25 turn pots).
2. Using a communications service monitor, generate a full-quieting 1 KHz test tone
at 60% channel deviation on the base station receive frequency. The input audio
level arriving at the Dual Channel Card must be between 0 dBm and -20 dBm. If a
communications service monitor is not available then make an incoming voice call
from a remote radio and do a "test count" at typical audio levels.
3. With the incoming test audio present, turn the appropriate Rx pot on the front of
the Dual Channel Card (4W for four wire, or 2W for two wire) slowly clockwise
until the green "CALL" LED for the channel being adjusted just comes on.
4. If desired, the input voltage being adjusted can be monitored with a digital
voltmeter while doing the adjustment. To monitor the Rx voltage adjustment,
connect the digital voltmeter to the dual channel card front panel test points GND
and RX.
The green call LED should come on at about -20dBm. Note there is some
hysteresis in the adjustment, adjust such that the green call LED just comes on as
the Rx level pot is turned up (clockwise).