PM5366-PI PMC-Sierra, Inc., PM5366-PI Datasheet - Page 77

• Manufacturer Part Number: PM5366-PI
• Description: HIGH DENSITY 84/63 CHANNEL VT/TU MAPPER AND M13 MULTIPLEXER
• Manufacturer: PMC-Sierra, Inc.

PRELIMINARY
DATASHEET
PMC-2010672
9.3.1 Inband Code Detection
9.3.2 T1 Bit Oriented Code Detection
PROPRIETARY AND CONFIDENTIAL
The time required to acquire frame alignment to an error-free ingress stream,
containing randomly distributed channel data (i.e. each bit in the channel data
has a 50% probability of being 1 or 0), is dependent upon the framing format.
For SF format, the T1 framer will determine frame alignment within 4.4ms 99
times out of 100. For SLC®96 format, the T1 framer will determine frame
alignment within 13ms. For ESF format, the T1 framer will determine frame
alignment within 15 ms 99 times out of 100.
Once the T1 framer has found frame, the ingress data is continuously monitored
for framing bit errors, bit error events (a framing bit error in SF or a CRC-6 error
in ESF), and severely errored framing events. The performance data is
accumulated for each tributary. The T1 framer also detects out-of-frame, based
on a selectable ratio of framing bit errors.
The framer detects the presence of either of two programmable inband loopback
activate and deactivate code sequences in either framed or unframed data
streams (whether data stream is framed or unframed is not programmable) .
The loopback codes will be detected in the presence of a mean bit error rate of
up to 10 -2 . When the inband code is framed, the framing bits overwrite the code
bits, thus appearing to the receiver as a 2.6x10 -3 BER (which is within the
tolerable BER of 10 -2).
Code indication is provided on the active high loopback activate (LBA) and
loopback deactivate (LBD) status bits. Changes in these status bits result in the
setting of corresponding interrupt status bits, LBAI and LBDI respectively, and
can also be configured to result in the setting of a maskable interrupt indication.
The inband loopback activate condition consists of a repetition of the
programmed activate code sequence in all bit positions for a minimum of 5.08
seconds (± 40 ms). The inband loopback deactivate condition consists of a
repetition of the programmed deactivate code sequence in all bit positions for a
minimum of 5.08 seconds (± 40 ms). Programmed codes can be from three to
eight bits in length.
The code sequence detection and timing is compatible with the specifications
defined in T1.403, TR-TSY-000312, and TR-TSY-000303.
The presence of 63 of the possible 64 bit oriented codes transmitted in the T1
Facility Data Link channel in ESF framing format is detected, as defined in ANSI
ISSUE 1
65
HIGH DENSITY 84/63 CHANNEL VT/TU MAPPER
AND M13 MULTIPLEXER
PM5366 TEMAP-84