The FOI-3583 and FOI-3853 both provide complete electrical isolation for RS-422 communications. The units are transparent to all handshaking protocols and can accept data and clock signals up to a maximum rate of 12.288 Mbps. A regeneration switch on the FOI-3583 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 unit 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 traditional RS-422 cabling. Multimode optics on the units can extend the distance to 2km. A typical link consists of an FOI-3583 at the Data Communication Equipment (DCE) and an FOI-3853 at the Data Terminal Equipment (DTE) with five fiber optic cables between them.