Chapter 3: Product overview
LED Icon
Blinking
On (Solid)
Telephone line 1 is off-hook or call
is in progress.
Telephone service for line 1 is connected
and activated; on-hook.
Telephone line 2 is off-hook or call
is in progress.
Telephone service for Line 2 is connected
and activated; on-hook.
Indicator lights for the T25
The T25 has LED indicator lights to assist in troubleshooting.
Patterns: normal operation
The following table shows light patterns during normal operation.
Table 3: T25 light patterns: normal operation
Mode
Power
US/DS
Online
Tel 1 / Tel 2
AC power
On
On
= Connected to
the Internet (ultra-
high speed)
Flash
= Not
connected to the
Internet
On
= Internet
available
Off = Internet
not available
On
= On-
hook
Flash
= Off-
hook
Off =
disabled
No AC power
Off
Off
Off
Off
Firmware
upgrade
On
Flash
On
(normal
operation)
Patterns: startup sequence
The following tables show the T25 light patterns during each phase of the startup sequence.
There are two phases of startup; the telephony phase and the cable modem phase. Both are
outlined below.
Table 4: Telephony startup sequence
Power, US/DS,
Online
Telephone 1
Telephone 2 Description
Off
Off
Off
No power to modem
Flash
Flash
Flash
Power-on self-test
On
Flash
Off
Retrieving telephone network information
SURFboard
®
T25 Cable Modem with Xfinity Voice User Guide STANDARD Revision 2.0
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