6/1531-ANF 901 14 Uen F1 2013-11-29
9
P
REPARATIONS
Additional CPE network termination units placed between MX-ONE and
the network interface such as multiplexor, repeaters or converters, must
preserve a traceable timing to the reference source even in presence of
wander/jitter in incoming bit rate as per ITU-T recommendation or equiv-
alent ETSI specifications (note 2).
Any equipment that degenerate the timing characteristics shall only be
used with certain restriction. Refer to Reference specification (note 39
for timing accuracy requirement and chapter 3.4.2 Synchronization
configuration for DECT. on page 9.
Note:
1) Characteristics of stratum 3 timing reference
Accuracy, Adjustment Range 4.6 x10
-6
Pull-In-Range Must be capable of synchronizing to clock with
accuracy of +/-4.6 x 10
-6
Stability 3.7 x 10
-7
/day
Note:
2) Characteristics of network interfaces, bit rate and timing are
specified in:
•
ITU-T Recommendation G.823 (or equivalent ETSI EN 302 084)
“The control of jitter and wander within digital networks which are
based on the 2,084 kbit/s hierarchy”.
•
ITU-T Recommendation G.824(or equivalent ETSI EN 302 084)
“The control of jitter and wander within digital networks which are
based on the 1,544 kbit/s hierarchy”.
Note:
ETSI EN 300 175 -2 V2.3.1 (2010-06) Digital Enhanced Cordless
Telecommunications (DECT) Common Interface (CI); Part 2:
Physical Layer (PHL)
A free running MGU index 2 can provide synchronization to master
ELU31/4 board, with ELU31/4 index 4 mode can then all mgw receive
PCM synchronization. This must be used while using only SIP trunks.
Using free running MGU and having E1/T1 connected slip can occur to
the other station. To avoid slip alarm notification send buffer can be acti-
vated on the MGU board see description MGU, Media Gateway Unit
1/1551-ANF90136 for more information.
3.4.2
Synchronization configuration for DECT.
In MX-ONE, all media gateways must provide system clock to all ELU31
boards with an accuracy and stability better then +/- 5 PPM see Note:
1) Characteristics of stratum 3 timing reference on page 9. In addition,
a synchronization ring is required for all ELU31 boards (inter-ELU31
cable ring) for proper DECT synchronization. The network timing source
must be carefully planned so that all media gateways containing ELU31