Fig 2. Example of connection in Point-to-Point topology; Tx, Rx signals
Fig 3. Example of connection in Point-to-Point topology; Tx, Rx, RTS/DTR, CTS/DSR signals
Fig 4. Example of connection RS485(4W) interface devices
4.1.2. CONNECTION TO RS485 2-WIRE BUS
Most of the devices with RS485 interface use 2-wire RS485 bus for data transmission. Example connection of ADA-I91402 to
RS485(2W) in multi-point topology is shown below.
6
ADA-I91402
Rt
RTS-/DTR-
CTS+/DSR+
ADA-I91402
Interface
USB
RS422/ RS485
(4W) Terminal
Device with RS422 /
RS485(4W) interface
RS422/ RS485
(4W)Terminal
Tx+
Tx-
GND
Rx+
Rx-
RTS+/DTR+
CTS-/DSR-
GND
Tx+
Tx-
USB
Rx+
Rx-
RTS-/DTR-
CTS+/DSR+
RTS+/DTR+
CTS-/DSR-
Rt
Rt
Rt
USB
Computer PC
Device with RS422
interface
Terminal
RS422
Tx+
Tx-
GND
Rx+
Rx-
Rt
Rt
Rx+
Rx-
GND
Tx+
Tx-
USB
Interface
USB
Terminal
RS422
ADA-I91402
USB
Computer PC
Rt
Rt
Rx+
Rx-
GND
Tx+
Tx-
USB
ADA-I91402
USB
Interface
RS485 (4W)
Terminal
USB
Computer PC
