RS-422 to Fiber Optic Line Driver/Converter

Model 272A Optoverter™ - RS-422 to Fiber Optic Line Driver/Converter

Reference Manual

Table of Contents

1.0 General Description
2.0 Specifications
3.0 Installation
4.0 Operation
5.0 Troubleshooting
6.0 Power
7.0 Help

1.0 General Description

The Model 272A Optoverter™, 4 wire RS-422 to Fiber Optic Line Driver/Converter, provides the capability of extending the distance of an RS-422 network to 6600 feet. At the same time it provides the in-herent advantages of fiber transmission over optic cable, immunity to interference, safety, secure communications, etc.

2.0 Specifications

Electrical: Full duplex RS-422, 4 wire

Fiber Interface: Optimized for 62.5/125 micron fiber cable

Wavelength: 850nm

Speed: 0-2.5 MHz

Power Budget: with 62.5/125 micron fiber 12dB

Distance: Fiber - 2Km (distances could exceed 2Km depending on fiber loss.); RS-422 - per RS-422 specification

Connectors: Fiber = ST, RS-422 = DB-25 Female

Power: 115 VAC/60 Hz (220 VAC/50 Hz optional)

Size: 3.5" L x 2" W x .875" H

Environment: 0° to 50° C, 5 to 95% RH (no condensation)

3.0 Installation

3.1 RS-422

The RS-422 connector to the Model 272A allows for full duplex operation through a DB-25 female connector. Refer to the following chart for pin assignments.


DB-25F Data Direction
2 Data In -
14 Data In +
3 Data Out -
16 Data Out +

3.2 Fiber

The fiber optic end has been optimized for operation with 62.5/125-micron cable and comes equipped with ST type fiber optic connectors.

4.0 Operation

The Model 272A can be connected to any RS-422 device running at speeds up to 2.5 MHz. To connect the units, the connections 'Data In' are connected to the 2 wire data from the RS-422 equipment and the 'Data Out' provides a signal to the receive data pins of the RS-422 equipment. To connect the 272A to another 272A the fiber connector marked T should be connected to the far end fiber connector marked R, and the local R to the far end T.

5.0 Troubleshooting

To verify proper operation of a unit, a short piece of fiber optic cable, with ST connectors, can be used to connect the transmit output to the receiver input. Using an RS-422 piece of equipment that can operate in full duplex mode, send data into the converter and observe that the correct data is being received correctly.

6.0 Power

The Model 272A is powered by a small DC power adapter that sup-plies reduced DC voltage. In addition, power can be applied to the Model 272A by using pin 9 on the DB25 female connector and pin 7 as the ground connection. When using this pin, the input voltage should be +12VDC.

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301-924-7400 EXT 25 / 301-924-7400 EXT 25 / fax 301-924-7403

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