Sigrand SG-17B, Руководство пользователя

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To make the optimal choice for the bitrate, the parameters of the line
intended for the modems are to be taken into account. In case the line
parameters are unknown, the following procedure is recommended to
choose the bitrate:
•
Measure the line resistance with an ohmmeter (at one side, the
wire pair is short-circuited and at the other side the measurement
is carried out) and use Table 2 of Appendix to define the bitrate
range within which the connection is going to be robust.
•
The bitrate value is set via the command
rate
and the parameter
<value>
where
<value>
is the bitrate measured in Kb per
second. The bitrate value can be established with a step of 64 Kb
per second, in the range 192 to 15296 Kb per second.
> rate 15296
Configuration......
Configuration complete
>
•
When being a «Slave», the modem receives the values of bitrate
and linear coding from the «Master», through the standard G.hs
Preactivation (ITU-T G.994.1).
•
The process of establishing the connection will take 2-3 minutes.
3 attempts at establishing a connection are allowed.
•
If after the specified period of time the modems are not connected
(the light-emitting diode «DSL LINK» does not flash on), select a
lesser bitrate and try again with the new bitrate value.
3.3.3. Choosing the linear encryption
TCPAM encoding, used by modems for the transmission of G.991.2
standard, has several grades of the encryption algorithm complexity. With
high bitrates, versions with a greater number of modulation positions are
used (TCPAM64, TCPAM128) and with lower bitrates, modes with lesser
numbers of modulation positions (TCPAM16, TCPAM32) are applicable.
Also, with the increase of the encryption algorithm complexity, noise
Immunity of the channel
decreases, and vice versa.