19528P-85 (11-02)
©2002 David Clark Company Incorporated
XL-9V BATTERY MODULE INSTRUCTIONS
Introduction
The model XL-9V battery pack uses a 9 volt alkaline battery (NEDA #1604A) to provide power
to the headset ENC system. The XL-9V features an Auto Shut Off function to save the battery if
the power switch is left on when the headset is not in use. The Auto Shut Off feature operates
by sensing loss of microphone DC bias voltage when the headset is unplugged or aircraft audio
system is shut off.
A switch is provided inside the battery compartment (see Fig. 1) to control the Auto Shut Off
feature. The XL-9V is shipped from the factory with this switch in the DISABLE position,
which will provide continuous power to the ENC system whenever the power switch is on.
Note: Switch must be in the DISABLE position when XL-9V is used
with H10-76XL or any headset using a non-amplified microphone.
To Enable Auto Shut Off
The ENABLE position provides automatic shut off of power to the ENC system if the headset is
unplugged or the aircraft audio system power is turned off.
To operate the Auto Shut Off switch remove the battery, and using a small pointed tool gently
move the switch to the desired position. A blunt tool like a ballpoint pen is not recommended.
Replace battery.
Power Indicator
A bi-color LED, mounted on the top of the battery pack indicates the status of the battery
(see Fig. 2).
When the battery is good and the headset is powered, the LED will blink green approximately
once per second. When the battery is low, the LED will be red until the battery is fully discharged.
Fig. 1
Fig. 2
View into the battery compartment,
showing Auto Shut Off Switch
View of the top of the battery
module, showing LED
