Data acquisition by modem

For many applications, the use of an on-site computer to perform measurements or control processes is a good solution. A limitation of all of the data-acquisition systems which we have published up to now is that a direct electrical connection is required between the computer and the acquisition system. The system described here works via a modem, which allows data to be exchanged with the PC via the telephone line. This makes possible a considerable physical separation between the computer and the acquisition system. For example, one no longer needs to guess at the temperature in the weekend cottage: with a suitable sensor you can just ring up, log in and read it out.