TM Fiber-Optic Devices TOSLINK PRODUCT GUIDETM TOSLINK Optical Transmission Device TM TOSLINK is a data transmission device which uses optical signals instead of electrical signals. Its principal features are as follows: Electromagnetic noise has no effect on the transmission line. The transmission line does not radiate any electromagnetic noise. The device is as easy to handle as like a digital IC, and connector assembly is easy. Comparison of TOSLINK and photocoupler The function ability of TOSLINK is similar to that of a photocoupler. A photocoupler has light-emitting and light-receiving devices in one package. V CC It is used to transmit electrical signals in a circuit, for a very short distane. V CC TOSLINK can be imagined as follows: separate the emitting device from the receiving device in the center of a photocoupler, then re-connect the two Input Output devices using a long optical fiber cable. Because optical fiber is used as the transmission line, it is possible to transmit (a)Photocoupler V CC signals over long distances while isolating them using TOSLINK. V CC As a result, TOSLINK is also sometimes referred to as a long-distance photocoupler. Optical fiber Input Output Optical transmitting module Optical receiving module (b)TOSLINK Comparison of TOSLINK and photocoupler Electrical and optical transmission system Electrical data transmission systems consist of the following devices: a line driver and line receiver to amplify electrical signals, a twisted-pair (or coaxial) cable as Twisted the transmission line and electrical connectors linking the line driver and line pair Electrical input signal Electrical output signal or coaxial receiver to the electrical cable. cable Line Line Driver Receiver By contrast, TOSLINK consist of the following devices: a transmitting module Electrical Electrical connector connector which converts electrical signals into optical ones, a receiving module which (a) Data transmission by electrical wire reconverts optical signals into electrical ones, optical fiber cable as the Fiber-optic link transmission line and optical connectors to link the transmitting and receiving Electrical input signal Electrical output signal Optical fiber modules to the optical fiber cable. Transmitting Receiving Module Module In TOSLINK, a transmitting IC (LED driver) and LED are included in the Fiber-optic Fiber-optic connector connector transmitting module, and a receiving IC (waveform-reshaping circuit) and E/O converter O/E converter photodiode are included in the receiving module. The interface between LED Transmitting Receiving Photodiode Circuit Circuit transmitting and receiving ICs is at the transistor-transistor logic (TTL) or emitter coupled logic (ECL) levels. Because of this it is easy to make connections with (b) Data transmission using fiber-optic cables the other circuits. Data transmission system Note: TOSLINK is a trademark of Toshiba Corp. Raytela is a trademark of Toray Industries Inc. Eska Premier is a trademark of Mitubishi Rayon Co. Ltd. Sumiguide is a trademark of Sumitomo Electronic Industries Ltd. 2