User’s Guide – 900MHz Stereo Audio Transmitter & Receiver
11
Internal Settings
The AT900-32 transmitter and the AR900-32 receiver each have
internal jumpers and/or switches (on their respective printed circuit
boards) that are preset at the factory to provide the proper
configuration for most applications. The following sections
describe these settings, and provide guidelines for when it may be
necessary or desirable to modify them.
CAUTION!
The AT900-32 transmitter and the AR900-32 receiver both
contain sensitive electronic components on their
respective circuit boards. These devices can be
permanently damaged by static discharge if adequate
anti-static procedures are not observed. Such damage is
not covered by the Applied Wireless, Inc. Limited
Warranty. Before attempting to modify any of the internal
settings, discharge any static that may have accumulated
on your body by touching a metal object or surface that is
earth grounded, such as a cold water pipe. In addition,
your work area should be as static-free as possible (for
example, do not work in an area in which the floor is
covered by nylon carpeting).
In order to modify any internal settings, the unit’s circuit board
must be removed from the enclosure, as follows:
1.
Disconnect the power and audio cables from the unit.
2.
For the receiver, remove the antenna. For the receiver,
remove the
VOLUME
knob.
3.
For the transmitter, remove the two Phillips screws
securing the front panel.
4.
For the receiver, remove the two Phillips screws securing
the rear panel.
5.
The two long edges of the circuit board are retained in
lengthwise grooves along the inside walls of the enclosure.
Gently slide the circuit board out of the enclosure. As you
remove the circuit board, hold it by its edges only.
6.
Once the internal setting(s) have been modified as
necessary, reassemble the unit by reversing the steps above.
12
Applied Wireless, Inc.
Local/Distance (DX) Jumper (Receiver)
The AR900-32 receiver has an internal jumper that determines the
receiver’s RF sensitivity. The factory default position for this
jumper is the Distance (
DX
) setting, configuring the receiver for
maximum sensitivity. This is the appropriate setting for most
applications (to allow for maximum reception range). However, if
multiple AT900-32 transmitters are to be used in a common area
(so as to broadcast multiple audio programs), and any are set to
operate on numerically adjacent channels, there is a possibility of
interference from one channel to the adjacent channel. Switching
the jumper to the
LOCAL
setting on any receiver(s) that exhibit such
interference may reduce or eliminate this interference. To do this,
perform the following steps:
1.
Locate the
LOCAL
/
DX
jumper on the circuit board. In its
factory default position, the jumper connects the middle pin
of the 3-pin group to the
DX
pin, leaving the
LOCAL
pin
open.
2.
Remove the jumper from its default position, and reinsert it
such that it connects the middle pin to the
LOCAL
pin
(leaving the
DX
pin open).
