of intercity public telegraph services between Washington and Baltimore in 1844. During the Civil War, the military ordered medical supplies and transmitted casualty lists by telegraph, and it seems probable that some uses of the telegraph in its early decades involved medical consultations (Zundel, 1996).

In 1876, Alexander Graham Bell patented the telephone, a device for electronic speech transmission. Bell's investigations arose, in part, from experiments to develop multiplex telegraphy that would allow several telegraph messages to be sent simultaneously over the same wire.

Commercial applications quickly followed Bell's patent, and long-distance telephone links began to appear in the 1880s. Since then, a continuing stream of technological innovations has improved the usefulness of telephone communication. These innovations include manual switchboards to connect multiple telephone lines, loaded circuits to reduce distortion over long distances, vacuum tube amplifiers to boost signals, and automatic switching systems, to name just a few. Telephone circuits can also carry still and video images as well as audio signals and data, and radio signals have been used to extend the reach of telephone communication.

These technical advances significantly extended the foundation on which telemedicine could build. Furthermore, at least five generations of users have created and passed on a legacy of technologies, behaviors, and expectations that make telephone communication commonplace. Parents give children telephone toys and let them answer real telephones at an early age; adults who find a child answering their calls generally tolerate and even enjoy participating in this early education in telephone technology. The other technologies on which telemedicine relies, such as the personal computer work station, are at varying stages of integration into everyday personal life or health care delivery.

As context for the committee's evaluation framework, this chapter briefly reviews the development of telemedicine and provides examples of current clinical applications. Chapter 3 provides more background on the technical and human infrastructure that supports telemedicine.

Development Of Telemedicine

In April 1924, an imaginative cover for the magazine Radio



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