STANDARD PRODUCT
PM4328 TECT3
DATASHEET
PMC-2011596
ISSUE 1
HIGH DENSITY T1/E1 FRAMER
AND M13 MULTIPLEXER
“1x” – Slow
771
The method for transferring DS3 link rate information across the SBI passes the
encoded count of DS3 clocks between 2KHz SC1FP pulses in the same method
used for T1 tributaries, but does not pass any phase information. The other
difference from T1 link rate is that ClkRate[1:0] indicates whether the nominal
number of clocks are generated or if four fewer or four extra clocks are
generated during the SC1FP period. The format of the DS3 link rate octet is
shown in Table 15. This is passed across the SBI via the Linkrate octet which
follows the H3 octet in the column, see Table 19. Table 16 shows the encoding of
the clock count, ClkRate[1:0], passed in the link rate octet.
Table 15: DS3 Link Rate Information
Link Rate Octet
DS3 Format
Bit #
7
0
6
0
5:4
ClkRate[1:0]
3:0
Unused
Table 16: DS3 Clock Rate Encoding
ClkRate[1:0]
DS3 Clocks / 2KHz
“00” – Nominal
“01” – Fast
“1x” – Slow
22368
22372
22364
SBI Alarms
The TECT3 transfers alarm conditions across the SBI bus for T1 tributaries. The
TECT3 does not support alarm conditions across the SBI bus for DS3.
Table 13 show the alarm indication bit, ALM, as bit 7 of the Link Rate Octet.
Devices connecting to the TECT3 which do not support alarm indications must
set this bit to 0 on the SBI ADD bus.
The presence of an alarm condition is indicated by the ALM bit set high in the
Link Rate Octet. The absence of an alarm condition is indicated by the ALM bit
set low in the Link Rate Octet. In the egress direction the TECT3 can be
configured to use the alarm bit to force AIS on a per link basis.
PROPRIETARY AND CONFIDENTIAL
161
PMC [ PMC-SIERRA, INC ]
