PM5366-PI PMC-Sierra, Inc., PM5366-PI Datasheet - Page 101

• 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
9.18 M12 Multiplexer (MX12)
PROPRIETARY AND CONFIDENTIAL
The M12 Multiplexer (MX12) integrates circuitry required to asynchronously
multiplex and demultiplex four 1544 kbit/s streams into, and out of, an M12
formatted DS2 serial stream as defined in ANSI T1.107 Section 7. The M12
multiplexer also supports the ITU-T Rec. G.747 standard for the multiplexing of
three 2048 kbit/s streams into a 6312 kbit/s stream.
When multiplexing four DS1 streams into an M12 formatted DS2 stream, the
MX12 function performs logical inversion on the second and fourth tributary
streams. Rate adaptation to the DS2 is performed by integral FIFO buffers,
controlled by timing circuitry. The FIFO buffers accommodate in excess of 5.0
UIpp of sinusoidal jitter on the DS1 clocks for all jitter frequencies. X, F, M, and
C bits are also generated and inserted by the timing circuitry. Software control is
provided to transmit Far End Receive Failure (FERF) indications, DS2 AIS, and
DS1 payload loopback requests. The loopback request is coded by inverting one
of the three C-bits (the default option is compatible with ANSI T1.107a Section
8.2.1 and TR-TSY-000009 Section 3.7).Two diagnostic options are provided to
invert the transmitted F or M bits.
When demultiplexing four DS1 streams from an M12 formatted DS2, the MX12
performs bit destuffing via interpretation of the C-bits. The MX12 also detects
and indicates DS1 payload loopback requests encoded in the C-bits. As per
ANSI T1.107 Section 7.2.1.1 and TR-TSY-000009 Section 3.7, the loopback
command is identified as C3 being the inverse of C1 and C2. Because TR-TSY-
000233 Section 5.3.14.1 recommends compatibility with non-compliant existing
equipment, the two other loopback command possibilities are also supported. As
per TR-TSY-000009 Section 3.7, the loopback request must be present for five
successive M-frames before declaration of detection. Removal of the loopback
request is declared when it has been absent for five successive M-frames.
DS1 payload loopback can be activated or deactivated under software control.
During payload loopback the DS1 stream being looped back still continues
unaffected in the demultiplex direction. The second and fourth demultiplexed
DS1 streams are logically inverted. All four demultiplexed DS1 streams can be
replaced with AIS on an individual basis or can be configured for automatic
replacement with AIS on detection of out of frame or RED alarm conditions.
Similar functionality is supplied for supporting ITU-T Recommendation G.747.
Software control is provided to transmit Remote Alarm Indication (RAI),
6312 kbit/s AIS, and the reserved bit. A diagnostic option is provided to invert the
transmitted frame alignment signal and parity bit.
When demultiplexing three 2048 kbit/s streams from a G.747 formatted
6312 kbit/s stream, bit destuffing is performed via interpretation of the C-bits.
ISSUE 1
89
HIGH DENSITY 84/63 CHANNEL VT/TU MAPPER
AND M13 MULTIPLEXER
PM5366 TEMAP-84