Product manual

XStream-PKG-R™ RS-232/485 RF Modem – Product Manual v4.2B5

2.3. RS-485 (4-wire) and RS-422 Operation

2.3.1. DIP Switch Settings and Pin Signals

Figure 2.10. Figure 2.11.

RS-485 (4-wire) and RS-422 Pins used on the female RS-232 (DB-9)

DIP Switch Settings Serial Connector

Figure 2.12.

RS-485 (4-wire) and RS-422 with Termination (optional)

Termination is the 120 Ω resistor between T+ and T-.

DIP Switch settings are read and applied only while powering-on.

Table 2.3. RS-485/422 (4-wire) Signals and their implementations with the XStream-PKG-R RF Modem

DB-9 Pin

RS-485/422

Name

Description Implementation

2 T- (TA)

Transmit Negative

Data Line

Serial data sent from the XStream RF Modem

3 R- (RA)

Receive Negative

Data Line

Serial data received by the XStream RF Modem

GND

Signal Ground

Ground

7 R+ (RB)

Receive Positive

Data Line

Serial data received by the XStream RF Modem

8 T+ (TB)

Transmit Positive

Data Line

Serial data sent from the XStream RF Modem

9 PWR Power

Optional power input that is connected internally

to the front power connector

1, 4, 6

not used

Wiring Diagram: RS-485 (4-wire) Half-Duplex

Figure 2.13. XStream RF Modem in an RS-485 (4-wire) environment