All product specifications are subject to change without notice.

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Port Powered RS-232/485

Converters

Models 4WSD9R, 4WSD9TB

Models 4WSD9TB and 4WSD9R, universal serial converters, provide RS-232

to RS-422/RS-485 conversion using either port-power or an external power

supply. Model 4WSD9TB has a terminal block RS-485 connector; Model

4WSD9R has a DB9 female RS-485 connector.

Data is converted in both directions, RS-232 Transmit Data is converted to

balanced RS-422 or RS-485 Transmit Data. Received RS-422/485 signals are

converted to RS-232. Unlike converters which require programming hardware

handshaking signals to control RS-422 or RS-485 operation, Models 4WSD9TB

and 4WSD9R provide automatic Send Data Control. In RS-485 mode, the

RS-485 driver is enabled by circuitry which senses the RS-232 TD input. In

half-duplex RS-485 mode, the receiver is enabled when not transmitting. For

full-duplex operation, the receiver is set always enabled.

In RS-422 mode, the transmitter and receiver are always enabled. The

operating mode is set with 4 switches see Table 1. The converters are

powered by the RS-232 signal lines whether they are set high or low. If not

enough power is available from the port, or no handshaking lines are available,

a DC jack is provided to connect an external 12VDC supply. The DB9 female

connector for RS-232 is wired as DCE (like a modem).

• Change RS-232 TD and RD to RS-485 signals

• Extend RS-232 data signals up to 1.2 km (4,000 ft.)

• Automatic Send Data Control

• Baud rates up to 115.2 kbps

• RS-232 port power or external 12 VDC power jack

• Dipswitch selectable RS-422 or RS-485

PRODUCT FEATURES

ACCESSORIES

SMI6-12-V-P230-C1 - Power Supply, 12 VDC 6 Watt, 2.5MM Plug, International AC

Input, International AC Blades

9PAMF6 - DB9 male to DB9 female adapter cable, 1.8 m (6 ft.)

ORDERING INFORMATION

MODEL

NUMBER

RS-232

CONNECTOR

(DCE)

RS-485

CONNECTOR

OUTPUT

OPTIONAL

POWER

SUPPLY

4WSD9R

DB9 Female

DB9 Female

RS-485 2 or 4-wire

or RS-422

✔

4WSD9TB

DB9 Female

Terminal Block RS-485 2 or 4-wire

or RS-422

✔

Table 1. RS-422/485 PINOUT

PIN #

SIGNAL

2

RD (A)-

3

TD (B) +

4

GND

6

GND

7

RD (B)+

8

TD (A)-

Table 2. RS-232 PINOUT

PIN #

SIGNAL

1

DCD

2

RD

3

TD

4

DTR

5

GND

6

DSR

7

RTS

8

CTS

No external power is required if two RS-232 output handshake lines are

available and the cable run is short. If the handshake lines are raised and no

termination is used, the power efficiency is greatly increased. Less than 3 mA

is required to operate the converter - plus the load current. For applications

that do not have handshake lines or require a large load current, power may

be externally supplied with a +12 VDC power supply with a 2.5mm plug (tip

positive).

The RS-232 port has a female DB9 connector with pins 2 (RD), 3 (TD), and 5

(Signal Ground) supported. Pins 7 (RTS) and 8 (CTS) are tied together, and pins

6 (DSR), 1 (DCD), and 4 (DTR) are also tied together. Any incoming data lines

in either the high or low state are used to port power the converter. The more

handshake lines available, the more likely the unit can be port powered. Table 2.

shows the RS-232 pinout.

Although handshake lines can be used to power the converter, no handshaking

is required to control the RS-422/RS-485 driver. With Switch 1 set to RS-422, the

driver is always enabled. When Switch 1 is in the RS-485 position, the RS-485

driver is automatically enabled during each spacing state on the RS-232 side.

During the marking or idle state, the RS-485 driver is disabled and the data lines

are held in the marking state by the 4.7K Ohm pull-up and pull-down resistors.

The value of these resistors may need to be changed to a different value when

termination is used in order to maintain the proper DC bias during the idle state.

4WSD9R_4WSD9TB_3417ds