The Modem and the Remote Control of Anaesthesiologic Activity

Abstract

Two computers located at a considerable distance can be connected by a telephone line. This technology is very similar to that of the fax-simile. In order to exchange commands, the two computers use a telephone cable, connected with the serial communication port. Thanks to the amplifiers used by the telephone company to send voice messages across considerable intercontinental distances, the telephone cable allows commands (which are actually voltage variations transformed into sounds) to arrive in an “intelligible” way at the serial ports of the two connected computers (Fig. 1). Remote transmission between two computers, therefore, consists of voice communication, which can only take place by means of a piece of equipment transforming computer signals into sounds and vice versa. The unit that makes this conversion possible is called “modem”. A modem is composed of two sections:

• 1. a telephone section which dials the telephone number and establishes the telephone connection;

• 2. a conversion section converting the signals emitted by the serial port of the computer into sounds and the sounds received from the telephone line into computer signals.