Phone: 91-79-4002 4896 / 97 / 98 (M) 0-98253-50221
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LED Indication:
A
Power
Power to the unit
B
TD
TX Data on RS485
C
RD
RX Data on RS485
D
DSR
Transmit Control
TABLE III: RS 232 Cable
Computer End
RS232 Port on LD-15U
Pin No on (D-25)
Pin No on (D-9)
Signal
Pin No (D-9, F)
Signal
2
3
Tx
2
Tx
3
2
Rx
3
Rx
6
6
DSR
6
DTR
7
5
GND
5
Sig. Gnd
20
4
DTR
4
DSR
4,5
7,8
RTS.CTS
8
RTS
The above connections are for Standard PC COM Port. Please verify these
connections for any other system or terminal before making the cable.
LONG DISTANCE CABLE LAYING
Long distance cable between two RS422/RS485 interfaces must be a twisted pair
shielded cable. The pair should be used for each signal type + and – signal. This
gives high common mode noise rejection. While laying the cable, care should be
taken not to lay this cable parallel to power line cables. The cable resistance should
not be more than 90 ohms/1000 meters. The cable should be run through conduit
pipe for physical protection.
