2820A-XX & 2825A-XX SERIES TWO DIVER COMMUNICATOR USER MANUAL
282XA-UM
REV 5.0
28
5.5.7
DIVER CUTS OFF
This is usually caused by an intermittent connection between either the umbilical
and the diver communicator or the umbilical and the diver's hat/helmet. The
intermittent connection could also be inside the diver's hat/helmet. Check all
connections to verify that they are clean and tight. If the problem continues,
substitute the communication cable with a known good cable. If this solves the
issue, then the communication cable in the original umbilical is damaged and
needs to be replaced or repaired. If none of these solutions fixes the problem,
contact Amron for further assistance.
5.5.8
FEEDBACK FULL DUPLEX (4-Wire) MODE
There are two forms of feedback that can affect the communicator: acoustic
feedback and cable crosstalk. Acoustic feedback occurs when an active
microphone is close enough to pick up and amplify the signal from a speaker or
earphone. The required distance between the microphone and speaker/earphone
is dependent on the volume setting and the amount of acoustic isolation. For
example, a tender headset left sitting on a work table my cause acoustic feedback.
When the tender dons the headset at the same volume level, the acoustic
feedback will no longer occur. The tender's head provides acoustic isolation
between the microphone and earphone of the headset. The same is true for the
diver's microphone and earphone.
To troubleshoot acoustic feedback issues first determine the source. One way to
quickly determine the source of the acoustic feedback is to cover each active
microphone with your hand, one at a time. Another method is to adjust the volume
controls one at a time. The volume control that stops the feedback indicates the
source. For example if the TENDER TO DIVER VOLUME control stops the
feedback, then the problem is likely in the diver's hat/helmet. Common sources are
feedback between the tender's headset microphone and the PANEL SPEAKER of
the communicator. If the tender wants to operate with the headset and leave the
PANEL SPEAKER on, Amron recommends the tender move away from the
communicator by using the Amron Model 2822-28 Remote Walk-and-Talk Module.
This module provides an "extension" cord for the tender headset allowing the
tender to operate away from the communicator.
Crosstalk is caused by signal leakage between the microphone and earphone
wires in the umbilical cable. In a good cable with all the wires open (not
connected), the resistance between any two wires should be greater than 10 Meg-
Ohms. Over time, the cable can be damaged and this resistance drops to the point
that crosstalk can occur. When this occurs, the communication cable in the
umbilical should be replaced. For a temporary solution, you can try swapping the
position of the diver earphone wires on the DIVER EARPHONE jack. If you are
using a banana plug, simply unplug the diver earphone and rotate by 180 degrees
before reconnecting. If this does not solve the problem and the umbilical cannot be
immediately replaced, then operate in 2-Wire mode until a replacement umbilical
can be used. Amron strongly recommends the use of the Amron CC1
communication cable. It has been specially designed for clear communications and
long service life.
Summary of Contents for 2820A
Page 2: ......
