Maxim DS33R11 specifications Error Counters, T1 Line Code Violation Counting Options, CVs

DS33R11 Ethernet Mapper with Integrated T1/E1/J1 Transceiver

10.7 Error Counters

The transceiver contains four counters that are used to accumulate line-coding errors, path errors, and synchronization errors. Counter update options include one-second boundaries, 42ms (T1 mode only), 62ms (E1 mode only), or manual. See Error-Counter Configuration Register (TR.ERCNT). When updated automatically, the user can use the interrupt from the timer to determine when to read these registers. All four counters saturate at their respective maximum counts, and they do not roll over. Note: Only the line-code violation count register has the potential to overflow, but the bit error would have to exceed 10E-2 before this would occur.

10.7.1 Line-Code Violation Counter (TR.LCVCR)

In T1 mode, code violations are defined as bipolar violations (BPVs) or excessive 0s. If the B8ZS mode is set for the receive side, then B8ZS codewords are not counted. This counter is always enabled; it is not disabled during receive loss-of-synchronization (RLOS = 1) conditions. Table 10-5 shows what the LCVCRs count.

Table 10-5 T1 Line Code Violation Counting Options

COUNT EXCESSIVE	B8ZS ENABLED?	COUNTED IN THE LCVCRs
ZEROS?
	(TR.T1RCR2.5)
(TR.ERCNT.0)
No	No	BPVs
Yes	No	BPVs + 16 consecutive 0s
No	Yes	BPVs (B8ZS codewords not counted)
Yes	Yes	BPVs + 8 consecutive 0s

In E1 mode, 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 codewords are not counted as BPVs. If TR.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 does not roll over. The bit-error rate on an E1 line would have to be greater than 10-2before the VCR would saturate (Table 10-6).

Table 10-6. E1 Line-Code Violation Counting Options

E1 CODE VIOLATION SELECT	COUNTED IN THE LCVCRs
(TR.ERCNT.3)
0	BPVs
1	CVs

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