Model 276A Optoverter
Reference Manual



Table of Contents

1.0 General Description
2.0 Specifications
3.0 Installation
4.0 Operation
5.0 Power
- Spanish Manual -


1.0 General Description

The Model 276A Optoverter(, 2 wire RS-485 to Fiber Optic Line Driver/Converter, provides the capability of extending the distance of an RS-485 network to 6600 feet. At the same time it provides the inherent advantages of transmission over fiber optic cable, immunity to interference, safety, secure communications, etc.
2.0 Specifications

2.1 Electrical: Half duplex RS-485, 2 wire

2.2 Fiber Interface: Optimized for 62.5/125 micron fiber cable

2.3 Wavelength: 850nm

2.4 Speed: 0-1.0 MHz

2.5 Power Budget: with 62.5/125 micron fiber 12dB

2.6 Distance:
Fiber - 2Km (distances could exceed 2Km depending on fiber loss.)
RS-485 - per RS-485 specification

2.7 Connectors: Fiber = ST, RS-485 = DB-25 Female

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

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

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

3.0 Installation

3.1 RS-485

The RS-485 connector to the Model 276A allows for half duplex operation through a DB-25 female connector. Refer to the following chart for pin assignments.

DB-25F Data Direction
2 Data I/O-
14 Data I/O+

3.2 Fiber

The fiber optic port has been optimized for operation with 62.5/125 micron cable and comes equipped with ST type fiber optic connectors for the transmit and receive fibers.

4.0 Operation

The Model 276A can be connected to any RS-485 device running at speeds up to 1 MHz. To connect the units, the connections 'Data In' are connected to the 2 wire data from the RS-485 equipment and the 'Data Out' provides a signal to the receive data pins of the RS-485 equipment. To connect the 276A to another 276A 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 Power

The Model 276A is powered by a small DC power adapter that supplies reduced DC voltage. In addition, power can be applied to the Model 276A 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.



For more information, contact:
Metrotek
Phone: (727) 547-8307
Fax: (727) 547-0687
E-mail: fiberoptics@metrotek.com

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