XRT84L38IB Exar Corporation, XRT84L38IB Datasheet - Page 347

• 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

REV. 1.0.1
Equipment (CPE). At the same time, a DS1 signal is routed from the CPE to the Repeater and back to the
Central Office.
When the E1 system runs normally, that is, when there is no Loss of Signal (LOS) or Loss of Frame (LOF)
detected in the line, no alarm will be generated. Sometimes, intermittent outburst of electrical noises on the line
might result in Bipolar Violation or bit errors in the incoming signals, but these errors in general will not trigger
the equipment to generate alarms. They will at most trigger the framer to generate interrupts which would
cause the local microprocessor to create performance reports of the line.
Now, consider a case in which the E1 line from the Repeater to CPE is broken or interrupted, resulting in
completely loss of incoming data or severely impaired signal quality. Upon detection of Loss of Signal (LOS) or
Loss of Frame (LOF) condition, the CPE will generate an internal Red Alarm, also known as the Service Alarm
Indication. This alarm will normally trigger a microprocessor interrupt informing the user that an incoming signal
failure is happening.
When the CPE is in the Red Alarm state, it will transmit the Yellow Alarm to the Repeater indicating the loss of
an incoming signal or loss of frame synchronization. This Yellow Alarm informs the Repeater that there is a
F
IGURE
112. S
Framer Block
DS1 Transmit
Framer Block
DS1 Receive
CO
Figure 112
IMPLE
D
IAGRAM OF
below shows the simple DS1 system model.
DS1 S
Simple DS1 System Model
YSTEM
Transmit
Receive
Section
Section
DS1
DS1
M
ODEL
Repeater
327
Transmit
Receive
Section
Section
DS1
DS1
OCTAL T1/E1/J1 FRAMER
DS1 Transmit
Framer Block
Framer Block
DS1 Receive
CPE
XRT84L38