CTC Union SHRM03b TDM Series, Руководство пользователя

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that the signal can be effectively transmitted. This means,
however, that a long sequence of zeros in data stream will
cause problems, since the NTU receiving the signal relies on
the signal to recover the 2048kbps clock.
3.6.4.3 Ais
AIS or Alarm Indication Signal is a method to inform the remote connection
that there is a signal or sync problem with the E1. AIS is only valid in framed
mode E1, not in Unframed E1. The setting here of AIS enabled (on) or not (off)
and is for testing with AIS. When enabled, the E1 will transmit the AIS and it
should be confirmed at the remote device (AIS indication lit). After testing,
please turn AIS back off.
Example 1: When STU-R E1 RX line is dropped, STU-R sends the status to
STU-C via EOC or command, and then STU-C will send AIS (Alarm
Indication Signal) to DTE while AIS function is enabled.
Example 2: When SHDSL connection drops, STU-R and STU-C both send AIS
(Alarm Indication Signal) to DTE in the same time while AIS function is
enabled.
3.6.4.4 Build outs
The E1 line card supports both unbalanced E1 at 75 ohms and balanced E1 at
120 ohms. The settings for impedance are made here under the build out
menu setting.