SBSLITE Telecom Standard Product Data Sheet
Preliminary
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2010883, Issue 2
62
Figure 9 Frame Alignment State Machine
out-of-
frame-
alignment
in-frame-
alignment
3 consecutive out-of-place
C1FPs or
out-of-character alignment
Found C1FP and
not (out-of-character alignment)
10.15.5 SBI336S Multiframe Alignment
SBI336S multiframe alignment is communicated across the link by controlling the frequency of
the C1FP character. The most frequent transmission of the C1FP character is every four SBI336S
frame times. This is the SBI336S multiframe and is used when there are no synchronous
tributaries requiring signalling multiframe alignment on the SBI336S bus. When there are
synchronous tributaries on the SBI336S bus the C1FP character is transmitted every 48 frame
times. This is the CAS signaling multiframe and is the lowest common multiple of the 24 frame
T1 multiframe and the 16 frame E1 multiframe.
The SBI336S multiframe and signaling multiframe alignment is based a free running multiframe
counter that is reset with each C1FP character received. Under normal operating conditions each
received C1FP character will coincide with the free running multiframe counter. SBI336S
multiframe alignment is always required, SBI336S signaling multiframe alignment is optional
and only required when synchronous tributaries are supported with DS0 level switching.
10.16 Outgoing SBI336S Tributary Translator
The Outgoing SBI Tributary Translator block, OSTT, processes all timing information and
Channel Associated Signaling information for the tributaries on the outgoing SBI Bus or buses.
Input to this block is a 77 MHz SBI stream with all tributaries encoded in an internal format that
closely resembles the serial SBI format.
This block is transparent in TelecomBus mode.