DT Etherlink IV
User Manual
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3.2.2.2.5 AIS Detection
If this mode is enabled, the reception of an AIS through the E1 interface will cause the following:
a non-urgent alarm will appear
AIS will be transmitted to the remote device of the DSL
WARNING
IT IS RECOMMENDED TO ENABLE THE AIS DETECTION AND AIS
GENERATION MODES FOR ALL E1 NETWORK INTERFACES.
3.2.2.2.6
Е1 Clock Modes
The Etherlink_IV product family has different possibilities to synchronize E1 interfaces. Usually the
E1 interface takes the E1-clock from the E1-input and transmits it through the SHDSL link to the E1-
output (plesiochronous). But we also support external clocking, internal clocking and clocking
priorities.
Figure 3.12
. Е1 clock modes
From E1 network interface side to SHDSL line side the following clock sources can serve as
reference timing signals:
1.
External clock generator (
EXTERNAL
) (inside subrack/minirack/UTT4).
2.
Clocking from the first E1 input stream (
E1-1
) (if available).
3.
Clocking from the second E1 input stream (
E1-2
) (if available).
4.
Clocking from the third E1 input stream (
E1-3
) (if available).
5.
Clocking from the forth E1 input stream (
E1-4
) (if available).
6.
Clocking from the internal generator (
INTERNAL
).
With the
SETCLOCK
command, the user can configure the priority levels for the clock sources. The
device automatically switches to the clock source with the highest priority under conditions that
synchronization in this mode is possible.
EXTERNAL means a synchronization from an external clock generator corresponding to the
recommendation ITU-T G.703.10. If the input signal of the external clock is lost, the device switches
to another clock source according the priority level. Using the external clock in synchronization
priorities, this external clock should have the highest priority. If the external clock generator is
absent, it should not be included in the priority list.
E1 Stream TX
Priority Selection
Stuffing
Synchronization
SHDSL
TX
SHDSL
Side
Clock from E1
External
Oscillator
E1-1
E1-2
E1-3
E1-4
Internal
Oscillator
SHDSL
RX
Clock Recovery
From SHDSL line
E1 Stream
RX
E1
Side
