A&D Weighing BM-20 - Manual (Page 69)

BM series 67
15. Standard Input And Output Interface
15.1.
RS-232C Interface
The balance is a DCE device. Connect the balance to a personal computer (DTE) using a straight
through cable.
Transmission system : EIA RS-232C
Transmission form : Asynchronous, bi-directional, half duplex
Transmission rate : 10 times/second or 5 times/second (same as data refresh rate)
Data format : Baud rate : 600, 1200, 2400, 4800, 9600, 19200bps
Data bits : 7 or 8 bits
Parity : Even, Odd (Data bits 7 bits)
None (Data bits 8 bits)
Stop bit : 1 bit
Code : ASCII
D-Sub 9 pin assignments
Pin No. Signal name Direction Description
1 - - No connection
2 TXD Output Transmit data
3 RXD Input Receive data
4 - - No connection
5 SG - Signal ground
6 DSR Output Data set ready
7 RTS Input Request to send
8 CTS Output Clear to send
9 - - No connection
Signal names of the balance side are the same as the DTE side with TXD and RXD reversed.
Start bit
Data bits
Parity bit
Stop bit
-5V to -15V
+5V to +15V
RS-232C
Balance side
DCE
Computer side
DTE
Inside of balance Terminal example
+5V
TXD 2
RXD 3
RTS 7
CTS 8
DSR 6
SG 5
RXD
TXD
RTS
CTS
DSR
SG
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