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13. RS-232C SERIAL INTERFACE
The balance is a Data Communication Equipment (DCE) device. Connect the balance to a personal
computer (DTE) using a straight through cable.
Transmission system : EIA RS-232C (D-Sub 9-pin, female connector)
Transmission form : Asynchronous, bi-directional, half duplex
Transmission rate
: 20 times/second, 10 times/second or 5 times/second (same as data refresh
rate)
Data format
: Baud rate
: 600, 1200, 2400, 4800, 9600, 19200 bps
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.
0 1 2 3 4 5 6
LSB
MSB
1
0
-5V to -15V
+5V to +15V
RS-232C
Stop bit
Parity bit
Start bit
Data bits
2
3
7
8
6
5
TXD
RXD
RTS
CTS
DSR
SG
RXD
TXD
RTS
CTS
DSR
SG
Approx.5V
Inside of balance
Balance side
DCE
Computer side
DTE
Terminals sample
#4-40UNC
9 8 7 6
5 4 3 2 1