The FOI-3733 and FOI-3734 both provide complete electrical isolation for TTL and RS-422 communications. Inputs are accepted at TTL levels, while outputs are generated RS-422 levels. The units are transparent to all handshaking protocols and can accept data and clock signals up to a maximum rate of 2.5 Mbps. A regeneration switch on the FOI-3733 allows users to toggle between synchronous applications that require Send Timing (ST) and asynchronous or synchronous applications that require Terminal Timing (TT). The units have five fiber optic channels with each channel being an independent signal path for data and clock signals.

The units can be used in areas of high electrical noise or in and out of RF shielded enclosures. The fiber optic cable is not susceptible to interference caused by impulse noise, crosstalk, or EMI. Privacy of communications is also enhanced because the fiber optic cable does not radiate any emissions. FiberPlex recommends “R” units for high security applications because the units have added filtering and shielding for RFI suppression.

In addition, fiber optic cable offers much longer transmission distances than copper wiring. Multimode optics on the units can extend the distance to 2km. A typical link consists of an FOI-3733 at the Data Communication Equipment (DCE) and an FOI-3734 at the Data Terminal Equipment (DTE) with five fiber optic cables between them.