Intercoms

17 Jun 2008

Shortly after Alexander Graham Bell’s first telephones became well known, people used the principles behind his invention to create basic intercom systems. An intercom system is defined as a personal device that permits the exchange of verbal messages between two or more locations, in places where standard communication would be difficult or impossible. But even before the advent of the telephone, there were devices in use that were similar to the modern intercom. They were common in large offices, on ships and in military installations. Residential estates and manor homes also used these gadgets to relay instructions to workers or servants who were out of earshot. More than just a system of ropes and bells, they were called “speaking tubes” and consisted of hollow metal pipes, which conducted sound for long distance. We can observe this phenomena even today when visiting old buildings heated by water pipes that tend to conduct every sound from room to room whether desired or not.

A favorite toy of children constructed by connecting two cups together with a length of string can also be considered a type of intercom, as can the telegraph. Both of these devices form a closed rather than open system of communication. Of course modern intercoms have taken the concept to a whole new height, and the new wireless systems have provided an entirely different level of sophistication.

Present-day intercoms have multiple functions and come in many styles. Simple systems provide access control for the gates and doors of businesses and homes. When a visitor arrives he announces his presence and the occupant can decide whether or not to allow him to enter. More complex methods include the use of video along with the audio capabilities, making the identification of visitors easier and more foolproof and these intercoms are called audio video intercoms. Technological advances are now allowing even more sophisticated additions to the reporting system. Things like metal detectors or chemical sensors can be incorporated in areas where security is vital.

New devices known as voice-activated intercoms are also becoming popular. They are easily used to monitor babies and others who cannot operate regular control buttons but need attention.

Intercoms need not be restricted to two-way communication. An unlimited number of individuals can be connected through a centrally controlled wireless intercom. Such systems are commonly found in places where announcements and mass messages are required such as schools, supermarkets, hospitals and airports. These systems allow one person to communicate with everyone present, and also permit individuals to contact each other.