The FOI-2981, FOI-4982, and FOI-2983 all provide complete electrical isolation for audio communications. A typical link consists of either an FOI-2981 or an FOI-2983 at one end of the network transmitting optical signals to an FOI-4982 at the other end of the network with a single fiber optic cable.

Typical Application

• Input A: voice announcements
• Input B: background music
• Input C: dry contact for doorbell (must be supplied by customer) A doorbell buzzer is generated when this input is grounded.

Order of Precedence

• A (highest – overides B and C)
• C (overides B)
• B (lowest)

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. In addition, fiber optic cable offers much longer transmission distances than copper wiring. Multimode optics on the units can extend the distance to 2km.

Flexible Mounting and Powering Options

The FOI-2981, FOI-4982 and FOI-2983 are part of the FOI line of products designed for ruggedized mil applications. They are housed in the familiar FOI shielded can enclosure. For standalone applications the FOI-2981 and FOI-2983 can be powered by adding a PSQ-2909 AC supply or a PSQ-2920 DC power supply (not included) and the FOI-4982 can be powered with a PSQ-4909 AC supply or a PSQ-4920 DC supply. Optionally, up to 8 FOI units can be mounted on CMA chassis adapters and installed in an RMC-3101 or RMC-2101 rack mount chassis. The units are powered redundantly by a common back plane connection.