Optimization
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PHOENIX CONTACT
4-1
4
Optimization
4.1
Optimizing the SHDSL data rate
The cable length and cable cross section have a major influence on the SHDSL data rate.
In turn, the SHDSL data rate influences the maximum possible serial data rate.
The PSI-CONF configuration software calculates the expected SHDSL data rate from the
cable length and cable diameter. The SHDSL data rate determined in this way is the basis
for the maximum serial data rate.
If the calculated SHDSL data rate in SHDSL auto mode (automatic detection) does not cor-
respond to the real conditions, the following scenarios are possible:
1.
In the real application, the
SHDSL data rate
is
worse
than the configuration software
assumes. In the event of high data traffic, data packets may be lost.
2.
In the real application, the
SHDSL data rate
is
better
than the configuration software
assumes. Under some circumstances, a higher serial data rate is possible.
3.
The SHDSL cables are subject to strong external
sources of interference
.
Possible solutions are described below for scenarios 1 and 2. For scenario 3, solutions are
recommended under "Increasing immunity to interference" on page 4-2.
Scenario 1: DSL data rate is worse than assumed
Proceed as follows:
•
Establish the line in the field. Make sure that the DSL data rate is set to "automatic" (see
"Step 3: DSL line configuration" on page 3-6).
•
Using the diagnostic function, display the actual SHDSL data rate on the line (see "Di-
agnostic overview" on page 3-10).
•
On the computer, create the configuration project and set the SHDSL data rate to "man-
ual" (see "Step 3: DSL line configuration" on page 3-6).
•
Enter the DSL data rate that you measured on the real line. The real measured SHDSL
data rate will be
less
than the calculated setting.
The configuration software calculates a new, maximum possible serial data rate and adjusts
the SHDSL devices accordingly.
Scenario 2: serial data rate improvement
If your required serial data rate needs to be higher than the data rate recommended by the
program, you can proceed as follows:
•
Establish the line in the field. Make sure that the DSL data rate is set to "automatic" (see
"Step 3: DSL line configuration" on page 3-6).
•
Using the diagnostic function, display the real SHDSL data rate on the line (see "Diag-
nostic overview" on page 3-10).
•
Open the existing project and set the DSL data rate to "manual" (see "Step 3: DSL line
•
Enter the SHDSL data rate that you measured on the real line. It must be greater than
the setting calculated by the configuration software. Otherwise, there can be
no
im-
provement to the serial data rate.
If, despite this optimization, the desired serial data rate is not displayed in the program, you
need to operate your system with a lower serial data rate.