B&B Electronics 4WSD25OTB Datasheet

P#9150_4WSDxxOTB-0812ds - p1/4

www.bb-elec.com [e-mail] [e-mail]

International Office: 707 Dayton Road PO Box 1040 Ottawa, IL 61350 USA 815-433-5100 Fax [phone]

European Office: Westlink Commercial Park Oranmore Co. Galway Ireland [phone] Fax [phone]

PRODUCT INFORMATION B&B ELECTRONICS

Model Number

Description

4WSD9OTB

Converter with female DB9 RS-232 Connector

4WSD25OTB

Converter with female DB25 RS-232 Connector

7175

Power 2-position Terminal Block – one included

7372

Data 5-position Terminal Block – one included

9PAMF6

6ft. Serial Cable DB9M to DB9F

485PS2

120 VAC to 12 VDC Power Supply

PS2EU-1000

220/240 VAC to 12 VDC Power Supply; 2-Prong Euro Plug

PS2UK-1000

220/240 VAC to 12 VDC Power Supply; 3-Prong UK Plug

Models: 4WSD9OTB/4WSD25OTB

Isolated Universal Converters

RS-232, 4-wire RS-422, 2-wire or 4-wire RS-485

Features

 High Speed Communications. Supports data rates up to 115.2 kbps.
 Extended communications. Supports distances up to 4000 ft (1200 m).
 Removable terminal blocks for easy RS-422/RS-485 connections.
 Switchable modes. Supports 2-wire RS-485, 4-wire RS-485, and full duplex RS-422.
 Automatic RS-485 driver control. External software modifications are not required.
 2000 VAC isolation. Reliable in harsh electrical conditions.

Functional Description

Isolates and converts RS-232 signals into RS-422 / RS-485 signals and vice versa. Unlike other
converters, external software is not required to control data flow. The RS-232 input is wired for DCE and
interfaced through a female DB25 or DB9 connector. RS-422 or RS-485 signals are connected to a
removable terminal block. External power is applied to separate removable terminal block. A 10 – 48 VDC
power supply (not included) is required.

Ordering Information

P#9150_4WSDxxOTB-0812ds - p2/4

www.bb-elec.com [e-mail] [e-mail]

International Office: 707 Dayton Road PO Box 1040 Ottawa, IL 61350 USA 815-433-5100 Fax [phone]

European Office: Westlink Commercial Park Oranmore Co. Galway Ireland [phone] Fax [phone]

PRODUCT INFORMATION B&B ELECTRONICS

Switches

Switch 1 (Tx)

Switch 2 (Rx)

Switch 3

(bridge)

Switch 4

(bridge)

Operating Mode

RS-485 2-Wire Mode

(half duplex)

RS-485

Echo Off

2-Wire

2-Wire

RS-485 4-Wire Mode

(full duplex)

RS-485

Echo On

4-Wire

4-Wire

RS-422 4-Wire Mode

(full duplex)

RS-422

Echo On

4-Wire

4-Wire

Loopback Test Mode*

As Desired

Echo On

2-Wire

2-Wire

Operation

Configure operating mode using guidance in Table 1.
Common Applications are discussed in Figures 1 through 3.
RS-232 connection requires RD, TD, and Signal Ground. The remaining signals are

looped back within the converter as shown in Table 2.
In half duplex operation, the receiver is enabled when not transmitting (Echo Off).
In RS-422 mode, the driver is always enabled.
In RS-485 mode, the RS-485 driver is automatically enabled during each space state by

the presence of an RS-232 signal. When the RS-232 data is in a mark or idle state, the RS-

485 driver is disabled and the RS-485 data lines are held in a mark state by the bias

provided by a 4.7K Ω resistor. The value of this resistor may need to be changed

depending on the termination used.
Refer to B&B Electronics’ RS-422/RS-485 Application Note for detailed information

concerning RS-422 and RS-485 networks. This document is available for download at

http://www.bb-elec.com/tech_articles.

The loopback test mode switch is used with hyper terminal to verify the operation of the

converter. Additional troubleshooting guidance is available at http://www.bb-

elec.com/technical_library.asp.

Table 1 – Operating Mode Switch Settings

Used with HyperTerminal or another terminal program to confirm operation of data through converter.

Table 2 – RS-232 Pin-out