DS21455 Maxim Integrated Products, DS21455 Datasheet - Page 86

• Manufacturer Part Number: DS21455
• Description: Network Controller & Processor ICs Quad E1-T1-J1 Single -Chip Transceiver (S
• Manufacturer: Maxim Integrated Products

Specifications of DS21455

• Product: Framer
• Number Of Transceivers: 4
• Data Rate: 64 Kbps
• Supply Voltage (max): 3.465 V
• Supply Voltage (min): 3.135 V
• Supply Current (max): 328 mA
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Mounting Style: SMD/SMT
• Package / Case: BGA

15.1 Line Code Violation Count Register (LCVCR)
15.1.1 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 codewords 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
15.1.2 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
codewords 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
E1 CODE VIOLATION SELECT
COUNT EXCESSIVE
(ERCNT.0)
ZEROS?
Yes
Yes
No
No
(ERCNT.3)
0
1
B8ZS ENABLED?
(T1RCR2.5)
Yes
Yes
No
No
WHAT IS COUNTED IN THE
86 of 270
LCVCRs
BPVs
BPVs + 16 Consecutive Zeros
BPVs (B8ZS Codewords Not Counted)
BPVs + 8 Consecutive Zeros
BPVs
WHAT IS COUNTED IN THE LCVCRs
CVs