The Fiberlink 4040 Series digitally transmits four independent audio channels over one multimode or single mode fiber at 850, 1310 or 1550 nm. It is ideal for rental, staging, education and broadcast applications. The 4040 is the 1550 nm Singlemode Box Transmitter for the 4040 system.The FiberLink 4040 Series transmission systems are normally preset for immediate use with audio input circuitry set for balanced 600 Ohm input impedance and output set forbalanced audio. If a different protocol is desired, it can be easily selected using the flip switches located on the back panel of the unit. (See Audio Switch Setting.) There are indicator LEDs on the units for monitoring purposes and several user selectable options for configuring audio inputs and outputs. The FiberLink 4040 series optical transmission system is a configurable, adjustment-free transmitter/receiver pair that employs digital processing and transmission techniques to convey up to four 1-way channels of audio.The use of digital encoding assures high-quality noise-free transmissions that retain all of their initial parameters regardless of fiber optic cable attenuation. In addition, integral LED indicators are provided on each unit to continuously signify the presence of audio signals and, thus, the proper operation of each side of the system.