XRT86L30
REV. 1.0.1
SINGLE T1/E1/J1 FRAMER/LIU COMBO
problem further down the line and its transmission is not being received at the CPE. The Figure below
illustrates the scenario in which the DS1 connection from the Repeater to CPE is broken.
FIGURE 104. GENERATION OF YELLOW ALARM BY THE CPE UPON DETECTION OF LINE FAILURE
CPE declares Red
Alarm internally
CO
Repeater
CPE
Yellow
Alarm
DS1
Transmit
Section
DS1
Receive
Section
DS1 Receive
Framer Block
DS1 Receive
Framer Block
DS1
Receive
Section
DS1
Transmit
Section
DS1 Transmit
Framer Block
DS1 Transmit
Framer Block
The DS1 line is
broken
The Repeater, upon detection of Yellow Alarm originated from the CPE, will transmit a Blue Alarm, also known
as Alarm Indication Signal (AIS) to the CO. 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. The
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EXAR [ EXAR CORPORATION ]
