RS232 to Fiber optic ST converter

The ADP3134 allows any two pieces of RS232 asynchronous serial equipment to communicate full-duplex over two multi-mode fibers. Typical distances up to 2.5 miles (4km) are possible with no external power required. The ADP3134 supports both data signals at up to 115.2 kbps as well as the RTS/CTS handshake lines. This means the ADP3134 can replace short haul modems and isolators when connecting remote devices, while providing the EMI/RFI and transient immunity of optical fiber.

RS232 connections are provided on the same DB9 female connector, while the multi-mode fiber is connected via two ST connectors. The unit is port powered by the RS232 Transmit Data and handshake lines. When handshake lines are not available, or when using a low power RS232 port, the ADP3134 can be powered by an external 12VDC supply, drawing 50 mA max.

Connection of the ADP3134 is simple and straightforward. The DB9 female serial connector is used for connecting the RS232 data and handshake signals. The connector is pinned as a DCE device (input on Pin 3 and output on Pin 2.) This means that a straight through cable (M2092) can be used from your DB9 port from any DTE device such as a PC or terminal. For connecting to modems and other DCE devices, a null movem cable or adapter that swaps pins 2 & 3 is needed. Care should be taken that any output handshake lines be connected through to the ADP3134 to power the unit.