HMi Series Instruction Leaflet
Serial Port Pinout
For 4” (HMI04BU/HMI04CU)
COM1 and COM3 are RS-232 only
COM2
DB 9 Pinout for COM1 and COM3 RS-232
COM3 Not Used
COM3 Used
PIN
COM1
COM3
COM1
COM3
1
2 RX
RX
3 TX
TX
4
5 GND
GND GND
6
7 RTS
TX
8 CTS
RX
9
Not Use
d
Note: Blank=No connection.
COM2 Pinout for
RS-422 & RS-485
PIN
RS-422
RS-485
G GND GND
T+ TX+
TX+
T- TX-
TX-
R+ RX+
RX+
R- RX-
RX-
Note: Blank=No connection.
Note: For RS-485 Connect TX+ to RX+ and
TX- to RX-.
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