STANDARD PRODUCT
PM4351 COMET
DATA SHEET
PMC-1970624
ISSUE 10
COMBINED E1/T1 TRANSCEIVER
of basic frame, when CRC-4-to-non-CRC-4 interworking is declared, and
when the offline framer is out of frame.
This bit only has effect in E1 mode.
SIGAEN:
The SIGAEN bit enables the operation of the signaling aligner (SIGA) to
ensure superframe alignment of signaling bits between the backplane and the
transmit DS-1 stream. When set to logic 1, the SIGA is inserted into the
signaling bit data path before the T1-XBAS. When the signaling aligner is
used, the backplane frame alignment indication must also be changed to
indicate superframe alignment for the transmit backplane. When SIGAEN is
set to logic 0, the SIGA is removed from the circuit. It is recommended that
SIGAEN be set to logic 1 in T1 mode.
This bit has no effect in E1 mode.
OOCMFE0:
When in E1 mode, the OOCMFE0 bit selects between two modes of
operation concerning the transmission of E-bits when the COMET is out of
CRC-4 multiframe. When OOCMFE0 is logic 0, the COMET transmits ones
for the E-bits while out of CRC-4 multiframe. When OOCMFE0 is logic 1, the
COMET transmits zeroes for the E-bits while out of CRC-4 multiframe. The
option to transmit zeroes as E-bits while out of CRC-4 multiframe is provided
to allow compliance with the CRC-4 to non-CRC-4 interworking procedure in
Annex B of G.706.
This bit only has effect in E1 mode.
FDIS:
The FDIS bit allows the framing generation through the transmitter to be
disabled and the transmit data to pass through the transmitter unchanged.
When FDIS is set to logic 1, the transmitter is disabled from generating
framing. When FDIS is set to logic 0, the transmitter is enabled to generate
and insert the framing into the transmit data.
FBITBYP:
The FBITBYP bit allows the frame synchronization bit in the input data
stream, BTPCM, to bypass the generation through the XBAS and be re-
inserted into the appropriate position in the digital output stream. When
FBITBYP is set to logic 1, the input frame synchronization bit is re-inserted
into the output data stream. When FBITBYP is set to logic 0, the XBAS is
allowed to generate the output frame synchronization bits.
PROPRIETARY AND CONFIDENTIAL
88
PMC [ PMC-SIERRA, INC ]
