Ericsson RBS 2106 Reference Manual page 428

Transmission Interface Handling DS1 1544 kbit/s
•
•
This includes detection of the fault conditions LOF (Loss Of Frame),
LOS (Loss Of Signal), ERATE (Excessive error RATE), AIS (Alarm
Indication Signal, "Blue Alarm"), and RAI (Remote Alarm Indication).
It also includes a consequent action. The consequent action for the faults
LOF, LOS, ERATE, AIS and UAST (UnAvailable STate) downlink is
to send RAI patterns (...1111111100000000...) continuously on the 4
kbit/s link to the remote end. This is performed for at least one second.
Two PCM paths are supported: PCM-A and PCM-B.
54.3.2 Layer 1 Synchronization
Synchronization of the outgoing signals (on the transport network
interface) is according to AT&T T1.5 Service (TR 62411) dec. 1990,
chapter 6 "Synchronization and Timing".
Synchronization of layer 1 is either derived from one of the incoming
PCM paths or taken from a free running oscillator. A PCM path
•
•
cannot be used as reference source.
The synchronization of layer 1 is one of four states:
1.
2.
3.
426 (485)
Input jitter and wander tolerance according to AT&T Accunet
T1.5 Service 1990 (TR 62411). This tolerance is valid for PCM-A
and PCM-B respectively. The tolerance of relative phase
differance (that is, phase differance between PCM-A and PCM-B)
is 56 UI
PTP
Fault supervision of each PCM path is performed according to
−
ANSI T1.403, section 9 (1995)
−
AT&T T1.5, paragraph 7
with LOF (Loss Of Frame alignment), LOS (Loss Of Signal), AIS
(Alarm Indication Signal) or
that is "not available for synchronization" according to a
parameter in RBS DB
Both PCM-A and B can be used as reference source
PCM-A is selected as the reference source
PCM-A incoming is used to synchronize PCM-A outgoing
PCM-B incoming is used to synchronize PCM-B outgoing.
PCM-A can be used as reference source, PCM-B cannot
PCM-A is selected as the reference source
PCM-A incoming is used to synchronize PCM-A outgoing
PCM-A incoming is used to synchronize PCM-B outgoing.
PCM-B can be used as reference source, PCM-A cannot
PCM-B is selected as the reference source
PCM-B incoming is used to synchronize PCM-A outgoing
PCM-B incoming is used to synchronize PCM-B outgoing.
© Ericsson Radio Systems AB
— All Rights Reserved —
EN/LZT 720 0008 P2A
2001-11-28