ZKTeco InBio160, Руководство пользователя

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RS485 Communication 4.3
1. RS485 communication wires are made of internationally accepted RVSP wires (shielded twisted
pairs), which prove effective to prevent and shield interference. RS485 communication wires
should be connected by means of 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 operator panels at most, but
preferably should be connected with less than 32.
3. To eliminate signal attenuation in communication cables and suppress interference, if the bus
is longer than 300 meters, one 120ohm resistance is usually inserted between the first and last
access control operator panels on the RS485 bus.
4. For this access control operator panel, putting place 8 of the DIP switch to the ON position is
equivalent to parallel connection of one 120ohm resistance between the 485+ and 485- lines.
As shown in the figure below, put place 8 of the DIP switches of the first and last control
operator panels to the ON position.
Figure 4-2 RS485 Communication System Networking