3-3
Section
Sharing the Communications Power Supply
28
3-3-2 Determining the Communications Power Supply Method
This section provides a basic flow chart to determine which communications
power supply method to use. Use the flow chart below to determine the commu-
nications power supply on the trunk line. The current carried by each drop line
must be less than the permissible current which can be calculated with the for-
mula on page 27.
Provisionally determine the
location of the power supply.
Step 1
Are the power supply
specifications met?
Step 2
Determine the best location of the
power supply from the graphs.
Are the power supply
specifications met?
Calculate the best location
of the actual nodes.
Consider changing the
location of the power supply.
Consider using thick cable.
Are the power supply
specifications met?
Consider changing the location of
the power supply.
Consider using thick cable.
Consider changing the location of
high current consumption nodes.
Set the location for
the power supply.
Split the power supply
system by installing two or
more power supplies.
No
Yes
Yes
No
No
Are the power supply
specifications met?
No
Step 3
Yes
Yes
