![](http://datasheet.mmic.net.cn/Exar-Corporation/XRT79L71IB-F_datasheet_100145/XRT79L71IB-F_27.png)
PRELIMINARY
XRT79L71
12
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
To transmit the FERF/RDI indicator (upon Software Control)
To automatically transmit the FEBE/REI Indicator (in response to the Receive DS3/E3 Framer block
detecting Frmaing bit or CP-bit errors - DS3, C-bit Parity Applications)
To automatically transmit the FEBE/REI Indicator (response to the Receive DS3/E3 Framer block detecting
BIP-8 Errors - E3, ITU-T G.832 Applications)
To transmit the FEBE/REI Indicator (upon Software Control).
1.2.8
The Transmit DS3/E3 LIU Block
The purpose of the Transmit DS3/E3 LIU Block is to accept the outbound DS3/E3 data-stream from the
Transmit DS3/E3 Framer block, and to perform all of the following operations on the signal.
To encode into the B3ZS Line Code (for DS3 Applications) or the HDB3 Line Code (for E3 Applications)
To convert this outbound DS3 or E3 data-stream into a DS3/E3 line signal and transmit this signal to the
remote terminal equipment
To generate and transmit DS3 pulses that complies with the Isolated Pulse Template requirements per
Bellcore GR-499-CORE
To generate and transmit E3 pulse that complies with the ITU-T G.703 Pulse Template requirements for E3
applications.
1.2.9
The Receive DS3/E3 LIU Block
The purpose of the Receive DS3/E3 LIU Block is to receive a DS3/E3 line signal from the remote terminal
equipment, and to perform the following operations on this incoming line signal.
To decode this incoming signal from the B3ZS Line Code (for DS3 Applications) or from the HDB3 Line Code
(for E3 Applications) into a binary data-stream
To route this binary data-stream to the Receive DS3/E3 Framer block for further processing.
To insure that the XRT79L71 meets all of the following Receive requirements.
a. The Receive Sensitivity requirement for DS3 Applications (e.g., able to receive a DSX-3 type of signal
through at least 450 feet of cable loss).
b. The Receive Sensitivity requirement for E3 Applications (e.g., able to receive an E3 signal over 12dB of
cable loss).
c. To comply with the Category I and II Jitter Tolerance Requirements per Bellcore GR-499-CORE (for DS3
Applications)
d. To comply with the Jitter Tolerance Requirements per ITU-T G.823 (for E3 Applications)
e. To comply with the Interference Margin Requirements of 20dB, per ITU-T G.703 (for E3 Applications)
1.2.10
The Receive DS3/E3 Framer Block
The purpose of the Receive DS3/E3 Framer block is to acquire and maintain Frame Synchronization with the
incoming DS3/E3 data-stream that it receives from the Receive DS3/E3 LIU Block. As the Receive DS3/E3
Framer block performs this task, it will also do the following.
It will declare and clear the LOS defect condition
It will declare and clear the LOF/OOF defect condition
It will declare and clear the AIS defect condition
It will declare and clear the FERF/RDI defect condition
It will detect and flag the occurrences of P-bit, CP-bit and Framing bit errors (DS3 Applications)
It will detect and flag the occurrence of BIP-8 Errors (E3, ITU-T G.832 Applications)
It will detect and flag the occurrence of BIP-4 Errors (E3, ITU-T G.751 Applications)