September 28, 2004
AlphaEclipse 3600 Series A Sign Installation Instructions (9711-8001C)
34
Appendix
RS485 termination
What is RS485 termination?
When signs are connected together, it is necessary to terminate each end of the network. This is necessary to
make sure that the signs communicate with each other.
If signs are
not
correctly terminated, messages could be displayed improperly.
When is termination used?
RULE: Terminate the first and last sign in a network:
RULE: If a Converter Box III is used, treat the converter box as if it were a sign:
Te
r
mi
n
ated
ONE SIGN
TWO SIGNS
THREE SIGNS
FOUR SIGNS
Te
r
mi
n
ated
Te
r
mi
n
ated
Te
r
mi
n
ated
Not Te
r
mi
n
ated
Te
r
mi
n
ated
Te
r
mi
n
ated
Not Te
r
mi
n
ated
Not Te
r
mi
n
ated
Te
r
mi
n
ated
Te
r
mi
n
ated
Te
r
mi
n
ated
Conve
r
te
r
Box III + ONE SIGN
Conve
r
te
r
Box III + TWO SIGNS
Conve
r
te
r
Box III + THREE SIGNS
Conve
r
te
r
Box III + FOUR SIGNS
Te
r
mi
n
ated
Te
r
mi
n
ated
Te
r
mi
n
ated
Not Te
r
mi
n
ated
Not Te
r
mi
n
ated
Not Te
r
mi
n
ated
Te
r
mi
n
ated
Te
r
mi
n
ated
Not Te
r
mi
n
ated
Not Te
r
mi
n
ated
Not Te
r
mi
n
ated
Te
r
mi
n
ated
To terminate a Converter Box III, set
the switch on the
back
of the unit.