User manual

69 Chapter 5
5.2.2 RS-422 Signal Wiring
The RS-422 interface wiring is based on one-to-one principles. The trans-
mit lines on one side connect to the receive lines on the other side, and
vice versa. With RS-422, you can transmit and receive data simulta-
neously (full duplex). The connections are as follows:
The signals DSR, DTR and DCD are shorted internally on the cards when
operating in RS-422 mode.
Terminator Resistors Setup
A user can solder in termination resistors if necessary for impedance
matching. The card has two jumpers for termination resistors, but no
resistors are installed at the factory. Resistors are usually installed at both
ends of the communication lines. The value of each resistor should equal
the characteristic impedance of the signal wires used (approximately 120
Ohms or 300 Ohms). The following table shows every card’s terminator
resistor.
Table 5.5: PCL-743B/S, PCL-745B/S RS-422 Wiring Table
DTE (Male DB-9) Terminal DTE
Pin Signal Signal
1 TxD- RxD-
2 TxD+ RxD+
3 RxD+ TxD+
4 RxD- TxD-
5GND GND
6 RTS- CTS-
7 RTS+ CTS+
8 CTS+ RTS+
9 CTS- RTS-
Item Port 1 Port 2 Port 3 Port 4
PCL-740 TR1, TR2
PCL-743S/B
PCL-745S/B
TR1, TR2,
TR5, TR6
TR3, TR4,
TR7, TR8
PCL-746+ TR1, TR8 TR2, TR5 TR3, TR6 TR4, TR7
PCL-846A/B TR1 ~ TR4 TR5 ~ TR8 TR9 ~ TR12
TR13 ~
TR16