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IDT82P20416
16-CHANNEL SHORT HAUL T1/E1/J1 LINE INTERFACE UNIT
Functional Description
33
December 17, 2009
3.5
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.
3.5.1
BIPOLAR VIOLATION (BPV) / CODE VIOLATION (CV)
DETECTION AND BPV INSERTION
3.5.1.1 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 B8ZS/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 B8ZS/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,...).3.5.1.2 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.
3.5.2
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
IDT82P20416 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 Counte. Refer to
Table-16 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.
T1/J1 - An EXZ is detected
when any string of more
than 80 consecutive ‘0’s are
received.
E1 - An EXZ is detected
when any string of more
than 15 consecutive ‘0’s are
received.
B8ZS
An EXZ is detected when
any string of more than 7
consecutive
‘0’s
are
received.
An EXZ is detected when
any string of more than 7
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.