XRT86L30
SINGLE T1/E1/J1 FRAMER/LIU COMBO
REV. 1.0.1
On the other hand, the payload portion of a framed AIS pattern is all ones. However, a framed AIS pattern still
has correct framing bits. Therefore, the equipment further down the line can still maintain frame
synchronization as well as timing synchronization. In this case, no LOF or Red alarm will be declared.
"AIS16" is an AIS alarm that is supported only in E1 framing format. It is an all ones pattern in time slot 16 of
each E1 frame. As we mentioned before, time slot 16 is usually used for signaling and data link in E1,
therefore, an "AIS16" alarm is transmitted by the intermediate node to indicate that the data link channel is
having a problem. Since all the other thirty one time slots are still transmitting normal data (that is, framing
information and PCM data), the equipment further down the line can still maintain frame synchronization,
timing synchronization as well as receive PCM data. In this case, no LOF or Red alarm will be declared by the
equipment further down the line. However, a CAS Multi-frame Yellow Alarm will be sent by the equipment
further down the line to indicate the loss of CAS Multi-frame alignment.
The Transmit Alarm Indication Signal Select bits of the Alarm Generation Register (AGR) enable the three
types of AIS transmission that are supported by the XRT86L30 framer. The table below shows configurations
of the Transmit Alarm Indication Signal Select bits of the Alarm Generation Register (AGR).
ALARM GENERATION REGISTER (AGR) (ADDRESS = 0X0108H)
B
IT
B
IT
N
AME
B
IT
TYPE
BIT DESCRIPTION
N
UMBER
3-2
Transmit AIS
Select
R/W
These READ/WRITE bit-fields allows the user to choose which one of the
three AIS pattern supported by the XRT86L30 framer will be transmitted.
00 - No AIS alarm is generated.
01 - Enable unframed AIS alarm of all ones pattern.
11 - AIS16 pattern is generated. Only time slot 16 is carrying the all ones
pattern. The other time slots still carry framing and PCM data.
11 - Enable framed AIS alarm of all ones pattern except for framing bits.
12.5.2
How to configure the framer to generate Red Alarm
Upon detection of Loss of Signal (LOS) or Loss of Frame (LOF) condition, the Repeater will generate an
internal Red Alarm when enabled. This alarm will normally trigger a microprocessor interrupt informing the user
that an incoming signal failure is happening.
The Loss of Frame Declaration Enable bit of the Alarm Generation Register (AGR) enable the generation of
Red Alarm. The table below shows configurations of the of Frame Declaration Enable bit of the Alarm
Generation Register (AGR).
ALARM GENERATION REGISTER (AGR) (ADDRESS = 0X0108H)
B
IT
B
IT
N
AME
B
IT
TYPE
BIT DESCRIPTION
N
UMBER
6
Loss of Frame
Declaration Enable
R/W
This READ/WRITE bit-field permits the framer to declare Red Alarm in
case of Loss of Frame Alignment (LOF).
When receiver module of the framer detects Loss of Frame Alignment in
the incoming data stream, it will generate a Red Alarm. The framer will
also generate an RxLOFs interrupt to notify the microprocessor that an
LOF condition is occurred. A Yellow Alarm is then returned to the remote
transmitter to report that the local receiver detects LOF.
0 - Red Alarm declaration is disabled.
1 - Red Alarm declaration is enabled.
12.5.3
How to configure the framer to transmit Yellow Alarm
The XRT86L30 framer supports transmission of both Yellow Alarm and CAS Multi-frame Yellow Alarm in E1
mode.
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EXAR [ EXAR CORPORATION ]
