Description
A typical model consists of a microprocessor, a modem, and software (in EPROM) that implements the AX.25 protocol and provides a command line interface to the user. (Commonly, this software provides other functionality as well, such as a basic bulletin board system to receive messages while the operator is away.) Because the TNC contains all the intelligence needed to communicate over an AX.25 network, no external computer is required. All of the network's resources can be accessed using a dumb terminal.
The TNC connects to the terminal and a radio transceiver. Data from the terminal is formatted into AX.25 packets and modulated into audio signals (in traditional applications) for transmission by the radio. Received signals are demodulated, the data unformatted, and the output sent to the terminal for display. In addition to these functions, the TNC manages the radio channel according to guidelines in the AX.25 specification.
Read more about this topic: Terminal Node Controller
Famous quotes containing the word description:
“Once a child has demonstrated his capacity for independent functioning in any area, his lapses into dependent behavior, even though temporary, make the mother feel that she is being taken advantage of....What only yesterday was a description of the child’s stage in life has become an indictment, a judgment.”
—Elaine Heffner (20th century)
“The next Augustan age will dawn on the other side of the Atlantic. There will, perhaps, be a Thucydides at Boston, a Xenophon at New York, and, in time, a Virgil at Mexico, and a Newton at Peru. At last, some curious traveller from Lima will visit England and give a description of the ruins of St Paul’s, like the editions of Balbec and Palmyra.”
—Horace Walpole (1717–1797)
“Whose are the truly labored sentences? From the weak and flimsy periods of the politician and literary man, we are glad to turn even to the description of work, the simple record of the month’s labor in the farmer’s almanac, to restore our tone and spirits.”
—Henry David Thoreau (1817–1862)