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DS21Q55

13.1 Line Code Violation Count Register (LCVCR)

T1 Operation

T1 code violations are defined as bipolar violations (BPVs) or excessive zeros. If the B8ZS mode is set for the receive side, then B8ZS code words are not counted. This counter is always enabled; it is not disabled during receive loss of synchronization (RLOS = 1) conditions (Table 15-1).

T1 LINE CODE VIOLATION COUNTING OPTIONS Table 15-1

COUNT EXCESSIVE

B8ZS ENABLED?

 

ZEROS?

WHAT IS COUNTED IN THE LCVCRs

(T1RCR2.5)

(ERCNT.0)

 

 

 

No

No

BPVs

Yes

No

BPVs + 16 Consecutive Zeros

No

Yes

BPVs (B8ZS Code Words Not Counted)

Yes

Yes

BPVs + 8 Consecutive Zeros

E1 Operation

Either bipolar violations or code violations can be counted. Bipolar violations are defined as consecutive marks of the same polarity. In this mode, if the HDB3 mode is set for the receive side, then HDB3 code words are not counted as BPVs. If ERCNT.3 is set, then the LVC counts code violations as defined in ITU O.161. Code violations are defined as consecutive bipolar violations of the same polarity. In most applications, the framer should be programmed to count BPVs when receiving AMI code and to count CVs when receiving HDB3 code. This counter increments at all times and is not disabled by loss of sync conditions. The counter saturates at 65,535 and will not rollover. The bit error rate on an E1 line would have to be greater than 10** -2 before the VCR would saturate (Table 15-2).

E1 LINE CODE VIOLATION COUNTING OPTIONS Table 15-2

E1 CODE VIOLATION SELECT

WHAT IS COUNTED IN THE

(ERCNT.3)

LCVCRs

0

BPVs

1

CVs

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Maxim DS21Q55 Line Code Violation Count Register Lcvcr, T1 Line Code Violation Counting Options Table, T1 Operation