Model 9268 - RS-232 Optical Isolator with DB9 Connector

Reference Manual


Table of Contents

1.0 General Description
2.0 Specification
3.0 Installation
4.0 Connector Pin Assignments 
5.0 Power
6.0 Help

1.0 General Description

The Model 9268 RS-232 Optical Isolator provides for a complete full-duplex electrical isolation channel between two RS-232 devices without the need for external power. This isolation is an important consideration if a system uses different power sources, has noisy signals, or must operate at different ground potentials.

2.0 Specification

Interface: Conforms to the RS-232 Electrical Specification. Pins 2 and 3 - Receive and Transmit Data

Pins 7 and 8 - Request to Send and Clear to send

Pin 1 - Data Carrier Detect*

Pin 4 - Data Terminal Ready*

Pin 5 - Signal Ground

*can be used instead of RTS & CTS by reconfiguring internal jumpers

Connectors: DTE = DB-9M, DCE = DB-9F

Data Rate: 0 to 115, 200 Bps

Isolation: 2500 VAC

Power: None required, derived from incoming data signal and control signal on each side. A control signal must be present.

Size: 5.62" L x 2.02" W x 1.06" H

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

3.0 Installation

The Model 9268 has been designed so that the user need only connect their equipment to the proper DB-9 connector on this device. The female DB-9 connector is a DCE port and will connect to a DTE device, such as a terminal or PC. The male DB-9 connector is a DTE port and will connect to a DCE interface, like a dial-up modem. The direction of each signal is shown in Figure 1.


Figure 1: Direction of Signals

The Control Signals on the Model 9268 can be reconfigured as needed. DTR can be selected instead of RTS and DCD instead of CTS. To reconfigure the unit, carefully separate the top and bottom covers with a small screwdriver. The jumpers are located near each DB-9, as shown in Figure 2, and can be set according to the needs of your system. Once the jumpers are set, replace the cover, making sure that the end marked DCE is facing the female DB-9.


Figure 2: Model 9268 Jumper Positions

4.0 Connector Pin Assignments




Data Carrier Detect


Receive Data


Transmit Data


Data Terminal Ready


Signal Ground


Request to Send


Clear to Send

5.0 Power

The Model 9268 incorporates micro power DC-to-DC converters that generate the necessary power for operation. There are two sets of these circuits, one for each port, that power the unit with a data signal, control signal and ground connected to each side of the unit. These lines should source at least 40 mW each in their quiescent state for proper operation of the Model 9268.

6.0 Help

If you require assistance, please visit our Technical Support Center.


TELEBYTE warrants the equipment to be free from defects in material and workmanship, under normal and proper use and in its unmodified condition, for 12 months, starting on the date it is delivered for use. TELEBYTE's sole obligation under this warranty shall be to furnish parts and labor for the repair or replacement of products found by TELEBYTE to be defective in material or workmanship during the warranty period. Warranty repairs will be performed at the point of manufacture. Equipment approved for return for warranty service shall be returned F.O.B. TELEBYTE factory and will be redelivered by TELEBYTE freight prepaid, except for non-continental U.S.A. locations. Non-continental deliveries will be sent COD freight plus import/export charges.

The above warranty is in lieu of all other warranties, expressed or implied, statutory or otherwise, including any implied warranty of merchantability or fitness for a particular purpose. TELEBYTE shall not be liable for any damages sustained by reseller or any other party arising from or relating to any equipment failure, including, but not limited to consequential damages nor shall TELEBYTE have any liability for delays in replacement or repair of equipment.

Out of warranty equipment may be returned to the Hauppauge, NY customer service facility prepaid as described above. Return shipping charges will be billed to the customer. The repaired unit will have a 90-day warranty. In those cases where "NO TROUBLE" is found, a reduced charge will be billed to cover handling, testing and packaging.

Whether in or out of warranty, a Return Material Authorization (RMA) number is necessary and can be obtained by visiting our Technical Support Center.

Document 0315-0321 Rev A

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