Connect Tech Blue Heat/PCI PCI Serial Communications - Manual (Page 39)

Blue Heat/PCI User’s Manual, Connect Tech Inc.
39 Revision 0.11
Figure 14 below describes a 2 wire cabling scheme between a port on the Blue Heat/PCI
RS-422/485, Opto, Opto RS-422/485 or Universal Blue Heat/PCI RS-422/485 adapter to a port
on the RS-422/485 peripheral.
Figure 14: RS-422/485 wiring diagram (2 wire)
RTS +
RTS -
CTS +
CTS -
TxD +
TxD -
RxD +
RxD -
RxD + TxD +
RxD - TxD -
RTS -
CTS -
RTS +
CTS +
SR SR
Blue Heat/PCI RS-422/485 adapter
Universal Blue Heat/PCI RS-422/485 adapter RS-422/485 peripheral
2
1
3
4
5
6
7
8
9
RTS +
RTS -
CTS +
CTS -
RxD +
RxD -
TxD +
TxD -
TxD + RxD +
TxD - RxD -
RTS -
CTS -
RTS +
CTS +
SR SR
Blue Heat/PCI Opto adapter
Blue Heat/PCI Opto RS-422/485 adapter RS-422/485 peripheral
1
3
2
4
5
6
9
7
8
Note:
In half-duplex mode it is assumed on the Blue Heat/PCI Opto
adapter that TxD (-) is connected to RxD (-) and TxD (+) is
connected to RxD (+) via jumpers JA7, JB7, JC7, JD7 and
JA8, JB8, JC8, JD8.
Technical Tip:
The RS-422/485 electrical interface consists of a differential
signaling scheme. You should always connect the signals with
twisted pairs.