A voice-powered phone is a communication device that allows users to talk to each other using handsets, similar to conventional phones, but without the use of external power. This technology has been in use since at least 1944 for routine and emergency communications on board to enable communication between key locations on board even if power, including batteries, is no longer available. Sound-powered telephone circuits can have two or more stations on the same circuit. Circuits are always alive, so users just start talking instead of calling other stations. Voice-powered phones are usually not connected to telephone exchanges.
Video Sound-powered telephone
Operasi
The microphone transducer changes the sound pressure from the user's voice to a minute electrical current, which is then converted back into sound by the transducer at the receiver's node. The most significant difference between a regular phone and a phone that has sound is in microphone operation. Because the microphones used in most phones are designed to modulate the available electric current, they can not be used in voice transducers. Instead, most phones that use voice use a dynamic microphone. A common approach to transducer design is a balanced armature design because of its efficiency. The number of simultaneous listeners is limited because there is no signal amplification.
Voice-powered telephone circuits can be as simple as two handsets connected to a pair of cables, which are defined as the "talk" part of the circuit. Talk circuit can be realized through a pair of cables that are 50 km (30 miles) long. More complex circuits include magnets, selector switches, and bells to allow one user to select and call the other, defined as the "call" part of the circuit. The voice communications circuit ("speech") is completely separate from the "call" circuit, allowing communication to take place without external power.
Maps Sound-powered telephone
Usage
Voice-powered phones are widely used in naval vessels. A common example on US Navy ships is the "JL" circuit used by scouts to report visual contacts to the pilot's home and Combat Information Center (CIC). In this case there will be five stations on the circuit (hard reconnaissance, port reconnaissance, right view, pilot house and CIC).
The US Coast Guard regulations require this emergency communication capability in most of today's vessels and determine where the phone should be placed. Call-backed battery phone systems will not meet USCG Rules as they currently exist.
Other uses for today's voice-powered telephony technologies include emergency communications systems for multi-storey buildings, attractive bridges, ski lifts, and temporary locations where reliable communication is required. This type of system allows two or more parties to be able to talk to each other in areas that have lost power or when radio communication is hampered by loss and/or limitations of RF signals.
Ski lifts use voice-enabled phones extensively. Since there are only two handsets (rarely there are three, where there is a central station), the sound-powered phone is ideal. They are used to confirm the elevator action with other operators, as well as abnormal operation of the lifting machine.
Many different types of equipment have tried to replace voice-powered phones on ships; but because of the rugged, reliable, and energy-free nature of this communication device, it is still used in all US military vessels, commercial vessels and vessels.
References
External links
- Voice Supported Webpages
- How a voice phone works work
- US Navy Tips
- [1] Recording US Navy "growler" magneto
Source of the article : Wikipedia
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