2820A-XX & 2825A-XX SERIES TWO DIVER COMMUNICATOR USER MANUAL
282XA-UM
REV 5.0
16
4.2
BATTERY CONDITION
4.2.1
POWER ON – BATTERY CHECK
Turn power switch “ON” and observe the battery condition indicator. The battery
indicator will display the condition of the battery.
•
“STEADY GREEN” light indicates the battery has sufficient voltage to operate
the unit.
•
“BLINKING GREEN” light indicates the battery is low and will need charging
shortly, three hours of operating time remain.
•
“STEADY RED” light indicates the battery voltage is too low to operate the unit.
Communication should stop.
NOTE
: A battery, which has not been used for a period of time, will display a higher
voltage state when initially turned on, this will rapidly dissipate. This condition is
known as a surface charge, when the battery is placed under a load the voltage will
fall rapidly. It is a good idea to leave the unit on for five minutes before relying upon
the battery condition indicator.
4.3
BATTERY INSTALLATION
The 2820A-XX & 2825A-XX series communicators are supplied with a single 12V gel-cell,
sealed lead-acid battery. To remove and install the battery, remove the four brass thumb
screws from the front panel and lift unit out of the case. Set brass screws aside in a safe
place where they won’t be lost. Set unit on flat stable surface with front panel facing up.
Remove two screws on each side of the chassis. Lift out radio using the handles and set it on
its right side (side away from speaker). The 12V battery is now accessible. Lift out battery
and remove color-coded slide terminals. Install the battery and close unit in the reverse order.
4.4
MODES OF OPERATION
The 2820A and 2825A series have the ability to operate in either 2-Wire or Full Duplex (4-
Wire). Both the diver and tender can be connected in either mode and a combination of
modes can be used. If either the diver or the tender is wired in 2-Wire mode, the tender must
use a push-to-talk, either the PUSH-TO-TALK ALL SWITCH or PUSH-TO-TALK JACK, when
talking to the diver.
2-Wire
communication is defined as a single communication path, normally the diver is the
priority signal path – tender listens to diver. Signal reversing is accomplished by pushing the
PUSH-TO-TALK BUTTON – diver hears tender. Often times a 4-conductor communication
cable is used with 2 wires tied together as a pair for redundancy, this is still a 2-Wire system.
Since only one person can talk at a time, there is a level of discipline that goes with using 2-
Wire mode in order to obtain clear communication. One advantage of 2-Wire is that the
tender's microphone is not active unless one of the two push-to-talk controls, PUSH-TO-
TALK BUTTON or PUSH-TO-TALK JACK, are active. This eliminates any possible acoustic
feedback between the tender's microphone and the PANEL SPEAKER. It also prevents noise
from the surface reaching the diver and allows the tender to communicate with other
members of the surface crew without involving the diver.
Summary of Contents for 2820A
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