System information

FCD 901 48
Issue R2A, 07.2009
XMP1 Release 5.5 System Description
Functioning of the SETS
Page 3-16 Proprietary Information Aastra
3.6.6 Functioning of the SETS
The following diagram explains the functioning of the SETS in the SDH
expansion.
The SETS has eight configurable timing sources TS (1) to TS (8), i.e. eight
reference timing sources can be connected to the SETS. The reference
timing sources T1, T2 and T3 can be applied to timing sources TS(2) to
TS (8).
The following applies to the SDH expansion:
• The internal oscillator is permanently connected to TS (1) on a
hardware basis.
• TS (2) to TS (5) are used for clock T1.
• TS (6) is used for PDH clock T2.
• TS (7) is used for clock T3.
Selector switches SELECT A and SELECT B select one of the reference
timing sources via the clock sources. The priorities for these switches can
be adjusted at the Operator Terminal.
The reference clock made available at T4 can be recovered from reference
timing sources TS (2) to TS (5).
Oscillator
SETG
Autom.
squelch
SELECT
A
SELECT
B
SELECT
C
T4
T1: Any STM-N port
T2: Any plesiochronous port
1)
T3: Timing input (on the CPM-SWM)
T0
TS(8)
TS(7)
TS(6)
TS(5)
TS(4)
TS(3)
TS(2)
TS(1)
Recovered
clock
No clock
Non-recovered
clock
Reference timing sources
1)
Recommendations G.813 and ETS 300 462-5 include information on permissible jitter and
wander values. Due to their TU-12 pointer jitter, non-recovered 2 Mbit/s signals from SDH
networks must not be used as timing sources for downstream networks.
T0: Internal system timing interface
T4: Timing output (on the CPM-SWM)
Figure 3.7: SETS in the XMP1 SDH expansion
PET
T1
T1
T1
T1
T2
T3