Sharp JW-20CM - Manual (Page 49)

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From the previous page
Set LT (termination resistance) switch
• When a JW-20CM master module is at either
end the communication line, make sure to
set the termination resistance switch "ON."
Reference: Function of the termination resistance switch
If the communication line does not have a termination resistance, the high frequency signal will
be reflected at the ends of the cable. These reflected signals can collide with the original
communication signals, so that some stations will not be able to communicate normally. The
use of termination resistance suppresses reflected signals. If the termination resistance switch
on any of the stations in between the end of the cable is turned ON, the station will generate a
reflection wave signal or attenuate the original signal and may not communicate normally.
· When the trunk line has a branch in it, turn ON the termination resistance at the station on the
trunk cable.
· If you use a terminator (termination resistance made by Toko Denshi: ME-75) at the end of a
signal cable, turn OFF the termination resistance at the station on the end of the cable.
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Turn ON the termination resistance
switches on these two stations.
Trunk cable
"T" branch
Termination
resistance (ON)
Drop cable
(branch line should
be less than 400 mm)
Terminator Terminator
Less than 1 km
Terminator: ME-75