Telebyte Optoverter 276A Reference Manual

Model 276A

Optoverter

Page 1 of 3

1.0 General Description

2.0 Specifications

3.0 Installation

3.1 RS-485

3.2 Fiber 3

4.0 Operation

5.0 Power

6.0 Help

Reference Manual

0315-0306 Rev. B

Printed 02.04.02

Table of Contents

The Model 276A Optoverter is a two-wire RS-485 to Fiber Optic Line Driver/Converter that
can extend the distance of an RS-485 network to 6,600 ft. At the same time it provides the
inherent advantages of transmission over fiber optic cable, immunity to interference, safety,
secure communications, and more.

1.0 General Description

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2.0 Specifications

Electrical: Half-duplex RS-485, two-wire

Fiber Interface: Optimized for 62.5/125 micron fiber cable

Wavelength: 850 nm

Speed: 0-1 MHz

Power Budget: 12 dB (with 62.5/125 micron fiber)

Distance: Fiber 2 km (distances can exceed 2 km depending on fiber loss)

RS-485: Per RS-485 specification

Connectors: Fiber (ST), RS-485 (DB-25 Female)

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

Page 2 of 3

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

Environment: 0 to 50 deg

, 5 to 95% RH (no condensation)

C

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.

2

14

7

Data Direction

Data I/O
Data I/O +

Signal Groun

DB-25F

3.2 Fiber

The fiber optic end has been optimized for operation with 62.5/125-micron cable and comes
e

ed with ST-type fiber optic connectors.

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 I/O-" and "Data I/O+" are connected to the two-wire

data from the RS-485 equipment. Pin 7 is Logic Ground (if the customer's equipment
requires it). 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" should be connecte
to the far-end "T."

4.0 Operation