PM8611-BIAP PMC [PMC-Sierra, Inc], PM8611-BIAP Datasheet - Page 39

• Manufacturer Part Number: PM8611-BIAP
• Manufacturer: PMC [PMC-Sierra, Inc]

10.1.4
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2010883, Issue 2
The DS3 and E3 method for transferring link rate information across the SBI passes the encoded
count of DS3/E3 clocks between C1FP pulses in the same method used for T1/E1 tributaries, but
does not pass any phase information. The other difference from T1/E1link 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 C1FP period. The format of the DS3/E3 link rate octet
is shown in Table 6. This is passed across the SBI via the Linkrate octet which follows the H3
octet in the column, see Table 12 and Table 15. Table 7 shows the encoding of the clock count,
ClkRate[1:0], passed in the link rate octet.
Table 6 DS3/E3 Link Rate Information
Table 7 DS3/E3 Clock Rate Encoding
Alarms
This specification provides a method for transferring alarm conditions across the SBI bus. This is
optional on a per tributary basis and is valid for T1, E1, DS3, E3 tributaries but not valid for
transparent VTs nor Fractional links.
Table 4 and Table 6 show the alarm indication bit, ALM, as bit 7 of the Link Rate Octet. Devices
which do not support alarm indications should set this bit to 0. When not enabled the value of this
bit must be ignored by the receiving device.
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.
The ALM bit is transparent to the SBS.
Link Rate Octet
DS3/E3 Format
ClkRate[1:0]
“00” – Nominal
“01” – Fast
“1x” – Slow
DS3 Clocks / 2 KHz
22368
22372
22364
Bit #
7
ALM
6
0
SBSLITE™ Telecom Standard Product Data Sheet
5:4
ClkRate[1:0]
E3 Clocks / 2 KHz
17184
17188
17180
3:0
Unused
Preliminary
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