S/UNI®-JET Data Sheet
Released
Valid X-bits are extracted by the T3-FRMR to provide indication of far end receive failure
(FERF). A FERF defect is detected if the extracted X-bits are equal and are logic zero
(X1=X2=0); the defect is removed if the extracted X-bits are equal and are logic one (X1=X2=1).
If the X-bits are not equal, the FERF status remains in its previous state. The extracted FERF
status is buffered for two M-frames before being reported within the DS3 FRMR Status Register.
This buffer ensures a better than 99.99% chance of freezing the FERF status on a correct value
during the occurrence of an OOF.
When the C-bit parity application is enabled, both the FEAC channel and the PMDL are
extracted. Codes in the FEAC channel are detected by the Bit Oriented Code Detector (RBOC).
HDLC messages in the PMDL 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.
10.2 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.
•
The FERF bit and indicates an alarm when the FERF bit is a logic one for three or five
consecutive frames. The FERF indication is removed when the FERF bit is a logic zero for
three or five consecutive frames.
•
The FEBE bit and outputs it for accumulation in PMON.
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-1990267, Issue 3
56
PMC [ PMC-SIERRA, INC ]
