16
RS485 Connection
Important Notes
#1 C3-200
#63 C3-200
RS485-
RS485+
GND
1. RS485 communication wires should be shielded or twisted pair calble.
RS485 communication wires should be connected in a bus cascade instead
of in a star form, to achieve a better shielding effect by reducing signal
reflection during communications.
2. A single 485 bus can be connected with 63 access control panels at the
most, but preferably less than 32 panels should be connected.
3. To eliminate signal attenuation in communication cables and suppress
interference, if the bus is longer than 200 meters, set the number 8 DIP
switch to the
ON
position. This is equivalent to a parallel connection of one
120ohm resistance between the 485+ and 485- lines.
Distance
More than 200 meters
#1 C3-200
#* C3-200
Do's and Dont's for RS 485 connection
