Black Box MT1000A-13-R3, Быстрый старт

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MT1000A Installation and Operation Manual Chapter 1 Introduction
Functional Description 1-5
Line coding is B8ZS or AMI. The nominal balanced interface transmit level is
±
3.0 V. The line attenuation is up to 12 dB, and each T1 signal is processed by an
adaptive equalizer that compensates for various cable lengths to ensure optimal
performance. Phase Locked Loops (PLL) are used to recover the clock signals, and
the resulting jitter performance complies with the requirements of ITU-T Rec.
G.824.
Each tributary interface has its own set of indicators that show the current state of
the tributary link. The user can disable the alarm indications generated by unused
interfaces (via internal switch and terminal, see
section 2.5 ). AIS data streams are
transmitted instead of failed or unconnected tributary data streams.
Test and Diagnostics Capabilities
MT1000A has comprehensive test and diagnostics capabilities that include local
and remote loopbacks on the fiber optic link interface and on each tributary link.
The activation is performed by sending a special test sequence through the fiber
optic link. An automatic self-test on power-up further enhances maintenance.
For more information on activating loopbacks see
Chapter 4 .
Alarms and Alarm Indications
MT1000A can detect the following alarm conditions on each T1 and fiber optic
interface:
•
Loss of input signal
•
Loss of frame synchronization
•
Reception of alarm indication (AIS) signal, which consists of a continuous
sequence of 1s.
•
When AIS is received, loss of frame synchronization occurs. However, in this
case the alarm indicating the loss of frame synchronization is suppressed.
•
AIS alarm will not appear for the non-active optical link.
When not all the tributaries are in use, the user can disable the alarm indications
related to the unused tributaries.
The response to alarm conditions is as follows:
•
AIS is transmitted on each tributary output in the following cases:
Loss of fiber optic input signal is detected
AIS is received on the fiber optic input
Loss of fiber optic frame synchronization.
• For each tributary, an AIS signal is sent instead of the tributary data stream
through the fiber optic link in the following cases:
Loss of tributary input signal is detected
AIS is received on the tributary input
Loss of tributary frame synchronization.
Notes