Actual results will vary, depending on, among other things, battery age, usage patterns, and environmental
conditions, including temperature extremes and fluctuations.
When to replace the ONT backup battery
For information about determining if a battery backup should be replaced, how and where to purchase a
replacement and how to install the replacement backup battery, see below or go to att.com/batterybackup.
First, determine which type of power supply unit (PSU) your ONT has by checking the serial number on the front
of the PSU (the serial number is designated with “S/N”). If the S/N starts with DAE, this is a Delta PSU. If the S/N
starts with CYB this is a CyberPower PSU. Otherwise, it is an APC model. The two APC PowerShield PSU models
look the same but have different features. To determine the model number, loosen the screws in the battery
compartment located at the bottom left of the PSU, lift up the PSU, and look at the model number on the back
of the unit. Also see the PSU images on page 42 for reference.
Delta One Piece PSU
The Replace Battery and Missing Battery status lights are on the front right of the Delta One Piece PSU. The
Replace Battery status light will be red if the battery needs to be replaced. An audible alarm will also sound, with
one beep every fifteen minutes, when the battery needs to be replaced. When the power supply begins using
battery power, it will beep once and then remain silent. If the battery begins to run low while running on battery
power, the alarm will beep four times per minute. The alarm can be silenced for 24 hours by pushing the blue
button on the front of the power supply. The Missing Battery status light will be green if no battery is connected
to the power supply.
Delta Two Piece PSU
There are status lights on the front right of the Delta Two Piece PSU. Refer to the Replace Battery status light,
third down from the top. It will be red if the battery needs to be replaced or if it is missing. An audible alarm will
also sound, with one beep every fifteen minutes, when the battery needs to be replaced. When the power supply
begins using battery power, it will beep once and then remain silent. If the battery begins to run low while running
on battery power, the alarm will beep four times per minute. The alarm can be silenced for 24 hours by pushing
the blue button on the front of the power supply. To determine if the battery is missing, open the door and look
for a battery; there is no audible alarm for a missing battery.
CyberPower PSU
There are status lights on the front right of the CyberPower PSU. The Replace Battery status light on the right will
be red if the battery needs to be replaced. An audible alarm also will sound with two beeps every three minutes
when the battery needs to be replaced. If the battery begins to run low while running on battery power, the alarm
will beep four times every two minutes. The alarm can be silenced for 24 hours by pushing and holding the blue
button on the front of the power supply for three seconds. This unit has a Missing Battery status light, which will
be red if no battery is connected to the power supply.
APC PowerShield PSU Model # CP24U12
There are status lights on the front right of the APC PSU. Refer to the Battery Status light. It will be red if the
battery needs to be replaced or if it is missing. There is no audible alarm on this unit. To determine if the battery
is missing, open the door and look for a battery; there is no audible alarm for a missing battery.
APC PowerShield PSU Model # CP27U13
There are status lights on the front right of the APC PSU. Refer to the Battery Status light. It will be red if the
battery needs to be replaced or if it is missing. An audible alarm will also sound, with one beep every fifteen
minutes, when the battery needs to be replaced. To determine if the battery is missing, open the door and look
for a battery; there is no audible alarm for a missing battery.
How to replace the ONT battery
Open the door, carefully pull the battery off the shelf, and remove the black and red wires. Connect the black (–)
and red (+) wires to the new battery, noting the proper battery polarity. Slide the new battery onto the shelf and
secure. Close the door.
Replacement Battery Model Number
GS Battery: PX12072-HG or GT12080-HG
Replacement batteries are widely available at:
• GS Battery (USA) Inc. (AT&T recommended provider): Call 800.472.2879
or visit gsbattery.com
• Batteries Plus
• Amazon.com
Note:
Locations where batteries are available are subject to change.
47
Battery Backup Information
