The FOI-3573 and FOI-3753 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. Data signals are transmitted and received on a 850nm wavelength, while clock signals are transmitted and received on a 1310nm wavelength. The units then use wave division multiplexing to combine and transmit the signals onto a single fiber. When the 850/1310nm combined signal is received, it is then separated by wave division demultiplexing.

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. A typical link consists of an FOI-3573 at the Data Communication Equipment (DCE) and an FOI-3753 at the Data Terminal Equipment (DTE) with a duplex fiber optic cable between them