STANDARD PRODUCT
PM4351 COMET
DATA SHEET
PMC-1970624
ISSUE 10
COMBINED E1/T1 TRANSCEIVER
• V5.1/V5.2 D-channel and C-channels.
• E1 Sa-bit data link
The RDLC detects the change from flag characters to the first byte of data,
removes stuffed zeros on the incoming data stream, receives packet data, and
calculates the CRC-CCITT frame check sequence (FCS).
In the address matching mode, only those packets whose first data byte matches
one of two programmable bytes or the universal address (all ones) are stored in
the FIFO. The two least significant bits of the address comparison can be
masked for LAPD SAPI matching.
Received data is placed into a 128-byte FIFO buffer. An interrupt is generated
when a programmable number of bytes are stored in the FIFO buffer. Other
sources of interrupt are detection of the terminating flag sequence, abort
sequence, or FIFO buffer overrun.
The Status Register contains bits which indicate the overrun or empty FIFO
status, the interrupt status, and the occurrence of first flag or end of message
bytes written into the FIFO. The Status Register also indicates the abort, flag,
and end of message status of the data just read from the FIFO. On end of
message, the Status Register indicates the FCS status and if the packet
contained a non-integer number of bytes.
9.10 T1 Alarm Integrator (ALMI)
The T1 Alarm Integration function is provided by the ALMI block. This block
detects the presence of Yellow, Red, and AIS Carrier Fail Alarms (CFA) in SF,
T1DM, SLC®96, or ESF formats. The alarm detection and integration is
compatible with the specifications defined in Bell Pub 43801, TA-TSY-000278,
TR-TSY-000008, ANSI T1.403-1993, and TR-TSY-000191. Alarm detection and
validation for SLC®96 is handled the same as SF framing format.
The ALMI block declares the presence of Yellow alarm when the Yellow pattern
has been received for 425 ms (± 50 ms); the Yellow alarm is removed when the
Yellow pattern has been absent for 425 ms (± 50 ms). The presence of Red
alarm is declared when an out-of-frame condition has been present for 2.55 sec
(± 40 ms); the Red alarm is removed when the out-of-frame condition has been
absent for 16.6 sec (± 500 ms). In T1DM framing format the Red alarm
declaration criteria can be selected to be either 400 ms (± 100 ms) or 2.55 sec
(± 40 ms); removal of the Red alarm in T1DM can be selected to be either
100 ms (± 50 ms) or 16.6 sec (± 500 ms). The presence of AIS alarm is
declared when an out-of-frame condition and all-ones in the PCM data stream
PROPRIETARY AND CONFIDENTIAL
49
PMC [ PMC-SIERRA, INC ]
