DS21455 Maxim Integrated Products, DS21455 Datasheet - Page 89

• 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

15.3 Frames Out Of Sync Count Register (FOSCR)
15.3.1 T1 Operation
The FOSCR is used to count the number of multiframes that the receive synchronizer is out of sync. This
number is useful in ESF applications needing to measure the parameters loss of frame count (LOFC) and
ESF error events as described in AT&T publication TR54016. When the FOSCR is operated in this
mode, it is not disabled during receive loss of synchronization (RLOS = 1) conditions. The FOSCR has
alternate operating mode whereby it will count either errors in the Ft framing pattern (in the D4 mode) or
errors in the FPS framing pattern (in the ESF mode). When the FOSCR is operated in this mode, it is
disabled during receive loss of synchronization (RLOS = 1) conditions. See
description of what the FOSCR is capable of counting.
Table 15-4. T1 Frames Out of Sync Counting Arrangements
15.3.2 E1 Operation
The FOSCR counts word errors in the frame alignment signal in time slot 0. This counter is disabled
when RLOS is high. FAS errors will not be counted when the framer is searching for FAS alignment
and/or synchronization at either the CAS or CRC-4 multiframe level. Since the maximum FAS word
error count in a one-second period is 4000, this counter cannot saturate.
The FOSCR1 (FOSCR1) is the most significant word and FOSCR2 is the least significant word of a 16-
bit counter that records frames out of sync.
FRAMING MODE
(T1RCR1.3)
ESF
ESF
D4
D4
COUNT MOS OR F-BIT ERRORS
(ERCNT.1)
MOS
F-Bit
MOS
F-Bit
89 of 270
Number of Multiframes Out of Sync
Errors in the Ft Pattern
Number of Multiframes Out of Sync
Errors in the FPS Pattern
WHAT IS COUNTED IN THE
Table 15-4
FOSCRs
for a detailed