The FOI-2395 and FOI-2935 are both very similar to the FOI-2591 and FOI-2951 in that data and clock signals are passed as balanced RS-422, while control signals have been changed to unbalanced RS-232. The units are transparent to all handshaking protocols and can accept data and clock signals up to a maximum rate of 256 kbps. A regeneration switch on the FOI-2395 allows users to toggle between synchronous applications that require Send Timing (ST) and asynchronous or synchronous applications that require Terminal Timing (TT).

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 traditional RS-422 cabling. Multimode optics on the units can extend the distance to 2km, while singlemode optics can further extend the distance to 20km. A typical link consists of an FOI-2395 at the Data Communication Equipment (DCE) and an FOI-2935 at the Data Terminal Equipment (DTE) with a duplex fiber optic cable between them.