RECENT DEVELOPMENTS
The introduction of radio into the telephone set has been the most important recent development in telephone technology, permitting first the cordless phone and now the cellular phone. In addition to regular telephone service, modern cellular phones also provide wireless Internet connections, enabling users to send and receive electronic mail and search the World Wide Web.
Answering machines and phones with dials that remember several stored numbers (repertory dials) have been available for decades, but because of their expense and unreliability were never as popular as they are today. Multifunctional telephones that use microprocessors and integrated circuits have overcome both these barriers to make repertory dials a standard feature in most phones sold today. Many multifunctional telephones also include automatic answering and message-recording capability.
Videophones are devices that use a miniature video camera to send images as well as voice communication. Videophones can be connected to regular telephone lines or their messages can be sent via wireless technology. Since the transmission of a picture requires much more bandwidth (a measure of the amount of data a system can transmit per period of time) than the transmission of voice, the high cost of transmission facilities has limited the use of videophone service.
This problem is being overcome by technologies that compress the video information, and by the steadily declining cost of transmission and video-terminal equipment. Video service is now used to hold business “teleconferences” between groups in distant cities using high-capacity transmission paths with wide bandwidth.
Videophones suitable for conversations between individuals over the normal network are commercially available, but because they provide a picture inferior to that of a television set, have not proven very popular. Television news organizations adopted the use of videophones to cover breaking news stories in remote areas. Their use escalated in 2001 during the U.S. war against terrorists and the Taliban regime in Afghanistan.
Telecommunications companies are rapidly expanding their use of digital technology, such as Digital Subscriber Line (DSL) or Integrated Services Digital Network (ISDN), to allow users to get more information faster over the telephone. Telecommunications companies are also investing heavily in fiber optic cable to meet the ever-increasing demand for increased bandwidth.
As bandwidth continues to improve, an instrument that functions as a telephone, computer, and television becomes more commercially viable. Such a device is now available, but its cost will likely limit its widespread use in the early part of the 21st century.
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