STANDARD PRODUCT
PM4351 COMET
DATA SHEET
PMC-1970624
ISSUE 10
COMBINED E1/T1 TRANSCEIVER
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DESCRIPTION
The PM4351 Combined E1/T1 Transceiver (COMET) is a feature-rich monolithic
integrated circuit suitable for use in long haul and short haul T1 and E1 systems
with a minimum of external circuitry. The COMET is software configurable,
allowing feature selection without changes to external wiring.
Analog circuitry is provided to allow direct reception of long haul E1 and T1
compatible signals with up to 36 dB cable loss (at 1.024 MHz in E1 mode) or up
to 36 dB cable loss (at 772 kHz in T1 mode) using a minimum of external
components. Typically, only line protection, a transformer and a line termination
resistor are required. Digital line inputs are provided for applications not
requiring a physical T1 or E1 interface.
The COMET recovers clock and data from the line and frames to incoming data.
In T1 mode, it can frame to several DS-1 signal formats: SF, ESF, T1DM (DDS)
and SLC®96. In E1 mode, the COMET frames to basic G.704 E1 signals and
CRC-4 multiframe alignment signals, and automatically performs the G.706
interworking procedure. AMI, HDB3 and B8ZS line codes are supported.
The COMET supports detection of various alarm conditions such as loss of
signal, pulse density violation, Red alarm, Yellow alarm, and AIS alarm in T1
mode and loss of signal, loss of frame, loss of signaling multiframe and loss of
CRC multiframe in E1 mode. The COMET also supports reception of remote
alarm signal, remote multiframe alarm signal, alarm indication signal, and time
slot 16 alarm indication signal in E1 mode. The presence of Yellow and AIS
patterns in T1 mode and remote alarm and AIS patterns in E1 mode is detected
and indicated. In T1 mode, the COMET integrates Yellow, Red, and AIS alarms
as per industry specifications. In E1 mode, the COMET integrates Red and AIS
alarms.
Performance monitoring with accumulation of CRC-6 errors, framing bit errors,
line code violations, and loss of frame events is provided in T1 mode. In E1
mode, CRC-4 errors, far end block errors, framing bit errors, and line code
violation are monitored and accumulated.
The COMET provides three receive HDLC controllers for the detection and
termination of messages on the ESF facility data link (T1) or national use bits
(E1) and in any arbitrary time slot (T1 or E1). In T1 mode, the COMET also
detects the presence of in-band loop back codes and ESF bit oriented codes.
Detection and optional debouncing of the 4-bit Sa-bit codewords defined in ITU-
T G.704 and ETSI 300-233 is supported. An interrupt may be generated on any
change of state of the Sa codewords.
PROPRIETARY AND CONFIDENTIAL
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PMC [ PMC-SIERRA, INC ]
