XRT86VL38
PRELIMINARY
xr
OCTAL T1/E1/J1 FRAMER/LIU COMBO
REV. P1.0.6
397
Next, let us consider the scenario in which the signaling and data link channel (the time slot 16) of an E1 line
between a far-end terminal (for example, the CO) and a near-end terminal (for example, the repeater) is
impaired. In this case, the CAS signaling data received by the repeater is corrupted. The Repeater will then
send an all ones pattern in time slot 16 (AIS16) downstream to the CPE. The repeater will also generate a CAS
Multi-frame Yellow Alarm upstream to the CO to indicate the loss of CAS Multi-frame synchronization.
Figure 104 below illustrates this scenario in which the Repeater is sending an "AIS16" pattern to the CPE while
sending a CAS Multi-frame Yellow Alarm to the CO.
F
IGURE
103. G
ENERATION
OF
Y
ELLOW
A
LARM
BY
THE
CPE
UPON
DETECTION
OF
AIS
ORIGINATED
BY
THE
R
EPEATER
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
Repeater
generates AIS
to CPE
AIS
Yellow
Alarm
CPE detects AIS and
generates Yellow
Alarm to Repeater