XRT79L71 datasheet(70/109 Pages) EXAR

70 / 109 page

XRT79L71

1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC - HARDWARE

REV. 1.0.0

f. To transmit FEAC (Far-End Alarm & Control) messages to the remote terminal equipment (DS3, C-bit

Parity Applications only).

g. To transmit LAPD/PMDL (Path Maintenance Data Link) Messages to the remote terminal equipment.

h. To transmit Trail-Trace Messages to the remote terminal equipment (E3, ITU-T G.832 Applications only).

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 the following functions on this data.

• Encode this data into the B3ZS/HDB3 Line code

• Convert this data-stream into a proper DS3 or E3 line code that complies with the following requirements.

a. The Isolated Pulse Template requirements per Bellcore GR-499-CORE (for DS3 Applications).

b. The ITU-T G.703 Pulse Template requirements (for E3 Applications).

The Receive DS3/E3 LIU Block

The purpose of the Receive DS3/E3 LIU Block is to receive an inbound DS3/E3 line signal from the remote

terminal equipment, and to perform the following functions on this data.

• To decode this data from the B3ZS/HDB3 Line code into a binary data-stream (prior to routing this data to the

Receive DS3/E3 Framer block

• To detect and flag the occurrence of LCVs (Line Code Violations) and EXZs (Excessive Zeros)

• To insure that the XRT79L71 meets all of the following Receive requirements

a. The Receive Sensitivity requirements 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 requirements 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)

The Receive DS3/E3 Framer Block

The purpose of the Receive DS3/E3 Framer block is to perform the following functions.

• To receive either a DS3 or E3 data-stream from the Receive DS3/E3 LIU Block. As the Receive DS3/E3

Framer block receives this DS3/E3 data-stream, it will do the following.

a. Compute and verify P and CP-bits (for DS3 Applications)

b. Compute and verify BIP-4 bits (for E3, ITU-T G.751 Applications)

c. Compute and verify BIP-8 bits (for E3, ITU-T G.832 Applications)

d. To declare and clear the LOS, OOF, LOF, AIS and FERF/RDI defect conditions

e. To declare and clear the DS3 Idle condition (DS3 Applications)

f. To detect FEBE/REI events.

The Receive PLCP Processor Block (Can be by-passed)

The purpose of the Receive PLCP Processor block is to perform the followoing functions.

• To receive the PLCP framd data-stream from the Receive DS3/E3 Framer block, and to acquire and maintain

PLCP frame synchronization with this data

• To declare and clear the PLCP OOF, PLCP LOF and PLCP RAI defect conditions

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