In the light loss in fiber, there are different factors involves, in which the three are most fundamental causes. Material loss, Light scattering and Waveguide & Bend losses Read more about Causes of Light Losses in Fiber Optics
Fiber optics principles, the principle on which fiber optics is based. i.e. step index, Total internal reflection, mode propagation, Meridional & Skew wave and more Read more about Principles of Fiber Optics
Transmitters that transmit AM signals are known as AM transmitters. These transmitters are used in medium wave (MW) and short wave (SW) frequency bands for AM broadcast. Read more about AM Transmitters
At the transmitter side, when the key is pressed, the telegraph signal current passes through the modulator, where high frequency signal from the osc is also received. Read more about Wireless Telegraphy
In tone dialing type of telephones, pressing the digit keys causes the dial network to produce specific tones that the central office recognizes and decodes.
A Rotary Or Mechanical Dial is an impulse sending device. When the subscriber lifts his handset, the D.C. loop is completed and steady current flows through the line provided by the exchange.
A teleprinter (teletypewriter, Teletype or TTY) is a electromechanical typewriter that can be used to communicate typed messages from point to point and point to multipoint over a variety of communication channels
Telegraphy is used to transfer information in the written form. It is a combination of two words. "Tele" means at a distance and "Graph" means to write. Hence telegraphy is to write at a distance.
In the light loss in fiber, there are different factors involves, in which the three are most fundamental causes. Material loss, Light scattering and Waveguide & Bend losses 
Transmitters that transmit AM signals are known as AM transmitters. These transmitters are used in medium wave (MW) and short wave (SW) frequency bands for AM broadcast. 