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XRT86VL38
PRELIMINARY
xr
OCTAL T1/E1/J1 FRAMER/LIU COMBO
REV. P1.0.6
395
The Repeater will also transmit a Blue Alarm, also known as Alarm Indication Signal (AIS) to the CPE. Blue
alarm is an all ones pattern indicating that the equipment is functioning but unable to offer service due to
failures originated from remote side. It is sent such that the equipment downstream will not lose clock
synchronization even though no meaningful data is received. Figure 102 below illustrates this scenario in
which the Repeater is sending an AIS to the CPE upon detection of line failure from the CO.
F
IGURE
101. G
ENERATION
OF
Y
ELLOW
A
LARM
BY
THE
R
EPEATER
UPON
DETECTION
OF
LINE
FAILURE
E1 Receive
Framer Block
E1 Transmit
Framer Block
E1 Receive
Framer Block
E1 Transmit
Framer Block
E1
Transmit
Section
E1
Transmit
Section
E1
Receive
Section
E1
Receive
Section
CO
Repeater
CPE
The E1 line is
broken
Repeater declares
Red Alarm
internally
Yellow
Alarm
Repeater generates
Yellow Alarm to CO