MDS 05-3438A01, Rev. F
MDS 4790/9790 Series I/O Guide
27
Coordinating Activities by Orderwire
The orderwire channel can be very useful in coordinating the set-up and
testing of two MDS 4790/9790 radios set up in a Polling Remote system
configuration. With a telephone handset plugged into the ORDERWIRE
jack (J9) on the radio’s rear panel, technicians can talk to each other
freely by merely speaking into the handset.
You can plug a telephone handset with a carbon microphone element
into J9 on the rear panel to communicate with someone at the radio link.
Handsets suitable for use with the radio are available from GE MDS
(Part No. 12-1307A01).
Normal system operation is unaffected if all you do is
listen
over the
handset. However, when you speak into the handset, the radio applies
transmit audio to an automatic voice-operated transmit keying (VOX)
circuit, keying the transmitter.
At the same time, the VOX circuit switches off external transmit data,
interrupting the normal flow of data in the system. Transmit audio from
the handset is then applied to the transmitter. Your voice is then heard
through a handset at the remote radio. Since any noise over the handset
interrupts transmission, you should unplug the handset when it is not in
use.
Troubleshooting Tip
You can listen to network data activity using the handset. While humans
cannot interpret the data by ear, the normal characteristics of the data
exchanges between the master station and remotes can be learned. Once
you know the “normal” pattern, you can recognize some changes as
abnormal. To prevent the interruption of payload data, remove or dis-
able the handset mouthpiece (microphone element). Using a handset as
an activity monitor is no substitute for electronic test equipment such as
a bite-error (BER) tester.
5.2 Front Panel Indicators
Refer to
Figure 24 on Page 28
and the following text for an explanation
of the front panel indicators. The control buttons are described in
Section 6.4,
Configuration and Programming using the Front Panel,
beginning on Page 60
.
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