PM7346 S/UNI-QJET
DATASHEET
PMC-960835
ISSUE 6
SATURN QUAD USER NETWORK INTERFACE FOR J2, E3, T3
When the C-bit parity application is enabled, both the far end alarm and control
(FEAC) channel and the path maintenance data link are extracted. Codes in the
FEAC channel are detected by the Bit Oriented Code Detector (RBOC). HDLC
messages in the Path Maintenance Data Link are received by the Data Link
Receiver (RDLC).
The T3-FRMR can be enabled to automatically assert the RAI indication in the
outgoing transmit stream upon detection of any combination of LOS, OOF or
RED, or AIS. The T3-FRMR can also be enabled to automatically insert C-bit
Parity FEBE upon detection of receive C-bit parity error.
The T3-FRMR extracts the entire DS3 overhead (56 bits per M-frame) using the
ROH output, along with the ROHCLK, and ROHFP outputs.
The T3-FRMR may be configured to generate interrupts on error events or status
changes. All sources of interrupts can be masked or acknowledged via internal
registers. Internal registers are also used to configure the T3-FRMR. Access to
these registers is via a generic microprocessor bus.
9.2 E3 Framer
The E3 Framer (E3-FRMR) Block integrates circuitry required for decoding an
HDB3-encoded signal and framing to the resulting E3 bit stream. The E3-FRMR
is directly compatible with the G.751 and G.832 E3 applications.
The E3-FRMR searches for frame alignment in the incoming serial stream based
on either the G.751 or G.832 formats. For the G.751 format, the E3-FRMR
expects to see the selected framing pattern error-free for three consecutive
frames before declaring INFRAME. For the G.832 format, the E3-FRMR expects
to see the selected framing pattern error-free for two consecutive frames before
declaring INFRAME. Once the frame alignment is established, the incoming
data is continuously monitored for framing bit errors and byte interleaved parity
errors (in G.832 format).
While in-frame, the E3-FRMR also extracts various overhead bytes and
processes them according to the framing format selected:
In G.832 E3 format, the E3-FRMR extracts:
•
the Trail Trace bytes and outputs them as a serial stream for further
processing by the Trail Trace Buffer (TTB) block;
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