Appendix a: rs232 adapter cables, Connection to a computer or terminal – Motorola 68P02958C00-B User Manual
Page 267
A-1
APPENDIX A:
RS232 Adapter Cables
This appendix provides the information required for connecting an RTU RS232 port to various
units, as detailed below:
•
Connection to a computer/terminal (MDLC protocol or User Port)
•
Connection to a modem (MDLC protocol or User Port)
•
Connection to a radio (MDLC protocol)
•
RTU-to-RTU connection using MDLC protocol through RS232 ports (RS-Link)
Connection to a Computer or Terminal
To connect one of the RTU RS232 Ports to a computer/terminal, you should use the FLN6457
adapter, which ends with the female 25-pin or 9-pin, D-type connector. The port may be
defined either as a MDLC protocol port or as a User Port.
The signals that appear on the female 25-pin or 9-pin D-type connector are according to the
RS232 standard – see the following table. In this case, the RTU serves as DCE (Data
Communication Equipment).
RS232 Function
8-pin Connector
(on RTU)
25-pin
Female
9-pin Female
Direction
TX-DATA
2
←
2
3
from DTE
RX-DATA
1
→
3
2
to DTE
RTS
5
←
4
7
from DTE
CTS
8
→
5
8
to DTE
DSR
7
→
6
6
to DTE
GND
4
7
5
-
DTR
3
←
20
4
from DTE
DCD (Rec line)
6
→
8
1
to DTE
To extend the cable, you may use any extension cable with male and female D-type connectors
(connected pin-to-pin, not crossed).
Note: When a User Port is defined as Computer/Terminal with DTR support:
1) The RTU will not transmit unless it receives DTR=ON from the computer/terminal.
2) The RTU will not receive unless it receives RTS=ON from the computer/terminal.