The ODW-621 is a fiber optic modem designed for point to point fiber optic applications between devices with an RS-232 interface.The ODW-621 is designed for harsh industrial usage as well as road or railway installations meeting industrial level EMC specifications and having a wide operating temperature range.The maximum distance of the fiber link depends on selected transceiver and fibertype.Fiber distances up to 80 km (50 miles) are possible using singlemode fiber.The unit has a retiming function that eliminates the problem of jitter and hence ensures reliable communications in all situations.It is possible to use the ODW-621 in conjunction with the ODW-631 to provide protocol conversion from RS-232 to RS-422/485 at either end of the optical link.