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IDT82P2521
21(+1) CHANNEL HIGH-DENSITY E1 LINE INTERFACE UNIT
Functional Description
42
December 7, 2005
3.4
DIAGNOSTIC FACILITIES
The diagnostic facilities include:
BPV (Bipolar Violation) / CV (Code Violation) detection and BPV
insertion;
EXZ (Excessive Zero) detection;
LOS (Loss Of Signal) detection;
AIS (Alarm Indication Signal) detection and generation;
Pattern generation and detection, including PRBS (Pseudo Ran-
dom Bit Sequence), ARB (Arbitrary Pattern) and IB (Inband Loop-
back).
The above defects, alarms or patterns can be counted by an internal
Error Counter, indicated by the respective interrupt bit and indicated by
RMFn or TMFn.
For diagnostic purposes, loopbacks and channel 0 monitoring can
also be implemented.
3.4.1
BIPOLAR VIOLATION (BPV) / CODE VIOLATION (CV)
DETECTION AND BPV INSERTION
3.4.1.1 Bipolar Violation (BPV) / Code Violation (CV) Detection
BPV/CV is monitored in both the receive path and the transmit path.
BPV is detected when the data is AMI coded and CV is detected when
the data is HDB3 coded. If the transmit system interface is in Transmit
Single Rail NRZ Format mode, the BPV/CV detection is disabled in the
transmit path automatically.
A BPV is detected when two consecutive pulses of the same polarity
are received.
A CV is detected when two consecutive BPVs of the same polarity
that are not a part of the HDB3 zero substitution are received.
When BPV/CV is detected in the receive path, the Line Bipolar Viola-
tion LBPV_IS bit (b4,
INTS2,...) will be set and an interrupt will be
reported by INT if not masked by the LBPV_IM bit (b4,
INTM2,...).When BPV/CV is detected in the transmit path, the System Bipolar
Violation SBPV_IS bit (b5,
INTS2,...) will be set and an interrupt will be
reported by INT if not masked by the SBPV_IM bit (b5,
INTM2,...).BPV/CV may be counted by an internal Error Counter or may be indi-
3.4.1.2 Bipolar Violation (BPV) Insertion
The BPV can only be inserted in the transmit path.
A BPV will be inserted on the next available mark in the data stream
to be transmitted by writing a ‘1’ to the BPV_INS bit (b6,
ERR,...). This
bit will be reset once BPV insertion is done.
3.4.2
EXCESSIVE ZEROES (EXZ) DETECTION
EXZ is monitored in both the receive path and the transmit path.
Different line code has different definition of the EXZ. The
IDT82P2521 provides two standards of EXZ definition for each kind of
line code rule. The standards are ANSI and FCC, as selected by the
When EXZ is detected in the receive path, the LEXZ_IS bit (b2,
INTS2,...) will be set and an interrupt will be reported by INT if not
When EXZ is detected in the transmit path, the SEXZ_IS bit (b3,
INTS2,...) will be set and an interrupt will be reported by INT if not
EXZ may be counted by an internal Error Counter or may be indi-
Table-8 EXZ Definition
Line Code
Rule
Definition
ANSI (EXZ_DEF = 0)
FCC (EXZ_DEF = 1)
AMI
An EXZ is detected when
any string of more than 15
consecutive
‘0’s
are
received.
An EXZ is detected when
any string of more than 15
consecutive
‘0’s
are
received.
HDB3
An EXZ is detected when
any string of more than 3
consecutive
‘0’s
are
received.
An EXZ is detected when
any string of more than 3
consecutive
‘0’s
are
received.
Note:
If the transmit system interface is in Transmit Single Rail NRZ Format mode, the EXZ is
detected according to the standard of AMI.