Kantronics KPC–3 Plus User Manual page 20

Packet radio gives you the ability to send essentially error-free digital communications
to other packet radio stations. As a sender or receiver, you see just the messages, or
files, being sent and received. But there is much going on beneath the surface. You will
get more out of packet radio, and have an easier time getting started, if you have at
least a basic understanding of what is involved in packet radio communication.
Do not be concerned here with how to do things —that comes later.
Three Basic Components of a Packet Radio Station
A packet radio station has three basic parts:
a transceiver, with an antenna,
a device called a TNC (i.e., Terminal Node Controller), which is a combination
modem and special-purpose micro-computer, and
Antenna
Transceiver
a general purpose computer (or a terminal).
The three parts of a packet radio station work together as follows:
The transceiver: (1) sends and receives radio signals to and from your antenna
and (2) passes audio signals back and forth between itself and the TNC.
The TNC (Terminal Node Controller): (1) translates audio signals into digital
information and vice versa, (2) performs a number of control and information
storage functions, and (3) communicates digitally with your computer.
The computer communicates digitally with the TNC, so you can: (1) view
messages received from the transceiver or stored in a mailbox (i.e., PBBS), (2)
use the computer to send data to, and receive data from, other stations, via the
TNC and your transceiver, and (3) control the operation of the TNC.
Sending a Message to Another Station
A quick way to see the basic components of packet radio in action is to follow a simple
message as it goes from one station to another, via an intermediate station.
KPC-3 Plus
TNC
Terminal Node Controller
20
Computer