ds21ft40 Maxim Integrated Products, Inc., ds21ft40 Datasheet - Page 40

• Manufacturer Part Number: ds21ft40
• Description: Ds21ft40 Four X Three 12 Channel E1 Framer
• Manufacturer: Maxim Integrated Products, Inc.

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 a E1 line would have to be
greater than 10** –2 before the VCR would saturate.
VCR1: UPPER BIPOLAR VIOLATION COUNT REGISTER 1 (Address=00 Hex)
VCR2: LOWER BIPOLAR VIOLATION COUNT REGISTER 2 (Address=01 Hex)
CRC4 Error Counter CRC4 Count Register 1 (CRCCR1) is the most significant word and CRCCR2 is the
least significant word of a 10–bit counter that records word errors in the Cyclic Redundancy Check 4
(CRC4). Since the maximum CRC4 count in a one second period is 1000, this counter cannot saturate.
The counter is disabled during loss of sync at either the FAS or CRC4 level; it will continue to count if
loss of multiframe sync occurs at the CAS level.
CRCCR1: CRC4 COUNT REGISTER 1 (Address=02 Hex)
CRCCR2: CRC4 COUNT REGISTER 2 (Address=03 Hex)
NOTE:
1. The upper 6 bits of CRCCR1 at address 02 are the most significant bits of the 12–bit FAS error
E–Bit Counter
E–bit Count Register 1 (EBCR1) is the most significant word and EBCR2 is the least significant word of
a 10–bit counter that records Far End Block Errors (FEBE) as reported in the first bit of frames 13 and 15
on E1 lines running with CRC4 multiframe. These count registers will increment once each time the
received E–bit is set to zero. Since the maximum E–bit count in a one second period is 1000, this counter
cannot saturate. The counter is disabled during loss of sync at either the FAS or CRC4 level; it will
continue to count if loss of multiframe sync occurs at the CAS level.
(note 1)
(MSB)
(MSB)
CRC7
V15
V7
SYMBOLS
SYMBOLS
counter.
CRC9
CRC0
V15
V0
V14
(note 1)
V6
CRC6
V13
V5
POSITION
POSITION
(note 1)
CRCCR1.1
CRCCR2.0
CRC5
VCR1.7
VCR2.0
V12
V4
(note 1)
CRC4
NAME AND DESCRIPTION
MSB of the 16–bit code violation count
NAME AND DESCRIPTION
MSB of the 10–Bit CRC4 error count
LSB of the 10–Bit CRC4 error count
LSB of the 10–bit code violation count
V11
V3
(note 1)
CRC3
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V10
V2
(note 1)
CRC2
V9
V1
CRC1
CRC9
(LSB)
V8
V0
CRC0
(LSB)
CRC8
VCR1
VCR2
CRCCR1
CRCCR2
DS21FT40