Beijing Huahuan Electronics H0EL-EthMux V8, Руководство пользователя

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Beijing Huahuan Electronics Co., Ltd
Huahuan
- 4 - H0EL-EthMux V8 User Manual V1.1
rebuilding the E1 clock at the destination is called Adaptive Timing.
For applications where separate clock distribution network exists, another timing
mode, Loop back Timing, may be used for maximum clock quality.
The two timing modes of H0EL-EthMux V8 are depicted in Fig.1.4-1.
Fig.1.4-1 E1Timing modes
Correct timing mode setting is important for smooth operations. In most cases,
setting both units to adaptive timing mode is sufficient. But sometimes, setting one
unit to loop timing mode may work better. For example, setting the H0EL-EthMux
V8 unit connected with the clock master (such as local exchange) to loop back mode,
and the other unit connected with the clock slave (such as PBX or remote module) to
adaptive mode, is probably better than setting both to adaptive modes.
One typical error in telecom applications is to connect two communication
devices that are both clock slaves. Neither will H0EL-EthMux V8 support such
operation no mater how the timing modes are set.
Note: that the E1channel emulation takes several minutes to stabilize.
During that period, clock drift may exceed the limit, errors and slips may occur.
Various timing schemes are enlisted in Table 1.4-1, for applications depicted in
Fig.1.4-2.
Fig.1.4-2 Timing mode scheme reference diagram
Table 1.4-1 Timing mode schemes
Equipment A
clock mode
Equipment B
clock mode
A side
EthMux V8
Timing mode
B side
EthMux V8
Timing mode
Note
master master
loop back loop back Equipment A & B
clocks synchronous
adaptive adaptive
master master adaptive adaptive
Equipment A & B
clocks plesiochronous