XRT84L38IB Exar Corporation, XRT84L38IB Datasheet - Page 388

• Manufacturer Part Number: XRT84L38IB
• Description: Network Controller & Processor ICs 8 Ch T1/E1 Framer
• Manufacturer: Exar Corporation

Specifications of XRT84L38IB

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

XRT84L38
OCTAL T1/E1/J1 FRAMER
The CPE, upon detecting the incoming AIS16 signal, will generate a CAS Multi-frame Yellow Alarm to the
Repeater to indicate the loss of CAS Multi-frame synchronization.
sending a CAS Multi-frame Yellow Alarm back to the Repeater
In summary, AIS or Blue Alarm is sent by a piece of E1 equipment downstream indicating that the incoming
signal from upstream is lost. Yellow Alarm is sent by a piece of E1 equipment upstream upon detection of Loss
of Signal, Loss of Frame or when it is receiving AIS.
Similarly, an "AIS16" pattern is sent by a piece of E1 equipment downstream indicating that the incoming data
link channel from upstream is damaged. The CAS Multi-frame Yellow Alarm is sent by a piece of E1 equipment
upstream upon detection of Loss of CAS Multi-frame synchronization or when it is receiving an "AIS16"
pattern.
11.5.2
As we discussed in the previous section, Alarm Indication Signal (AIS) or Blue Alarm is transmitted by the
intermediate node to indicate that the equipment is still functioning but unable to offer services. It is an all ones
(except for framing bits) pattern which can be used by the equipment further down the line to maintain clock
recovery and timing synchronization.
The XRT84L38 framer can generate three types of AIS when it is running in E1 format:
•
•
•
Unframed AIS is an all ones pattern. If unframed AIS is sent, the equipment further down the line will be able to
maintain timing synchronization and be able to recover clock from the received AIS signal. However, due to the
lack of framing bits, the equipment farther down the line will not be able to maintain frame synchronization and
will declare Loss of Frame (LOF).
F
TERN SENT BY THE
IGURE
Framed AIS
Unframed AIS
AIS16
124. G
Framer Block
Framer Block
How to configure the framer to transmit AIS
E1 Transmit
E1 Receive
CO
ENERATION OF
R
EPEATER
Repeater generates
Yellow Alarm to CO
CAS Multi-frame
The timeslot 16
of an E1 line is
CAS M
frame Yellow
iimpaired
CAS Multi-
Alarm
ULTI
-
FRAM
Transmit
Receive
Section
Section
E1
E1
Y
ELLOW
Repeater
368
A
Transmit
Receive
Section
Section
LARM BY THE
E1
E1
and generates CAS
CPE detects AIS16
Multi-frame Yellow
Alarm to Repeater
AIS16 to CPE
frame Yellow
CAS Multi-
generates
Figure 124
Repeater
CPE
AIS16
Alarm
UPON DETECTION OF
below illustrates the CPE
Framer Block
Framer Block
E1 Transmit
E1 Receive
CPE
“AIS16”
REV. 1.0.1
PAT
-