User manual

Chapter 5. Configure via Console Port
5-18
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Command: setup e1 code <AMI|HDB3>
Message: Please input the following information.
SHDSL E1 code (TAB Select) <HDB3>: HDB3
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HDB3
In this line coding, the transmitter substitutes a deliberate
bipolar violation when excessive zeros in the data stream
are detected. The receiver recognizes these special
violations and decodes them as zeros. This method
enables the network to minimum pulse density
requirements. Unless AMI is required for your
application, HDB3 should be used whenever possible.
AMI
Alternate Mark Inversion defines a pulses as a “mark,” a
binary one, as opposed to a zero. In an E1 network
connection, signals are transmitted as a sequence of
one and zero. One is sent as pulse, and zero is sent as
spaces, i.e. no pulse. Every other pulse is inverted from
the previous pulse in polarity, so that the signal can be
effectively transmitted. This means, however, that a long
sequence of zero in data stream will cause problems,
since the NTU receiving the signal relies on the signal to
recover the 2048kbps clock.
For configuring frame, move the cursor to frame and press [ENTER]. Select
the parameter via [TAB] key.
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code Configure e1 code
>> frame Configure e1 frame
rai Configure e1 rai
build_outs Configure e1 build outs
e_bit Configure e1 e_bit