27Inside a TNC – the KPC-3 PlusTo better understand the workings of your packet radio station, it is helpful to have anoverview of the major components of the TNC device at the center of your station.In the early days of packet radio, TNC‘s consisted primarily of a modem forcommunicating with a transceiver and a special-purpose microprocessor called a PAD(i.e., packet assembler/disassembler) used to process packets of information andcommunicates with a computer or terminal.As packet radio has developed, more and more features have been added, such asmemory and software dedicated to a ―Personal Bulletin Board System‖ within theTNC. The following diagram shows the most important internal components of aTNC (the KPC-3 Plus). The diagram is not to scale. For a detailed example, see theparts list and layout diagram for the KPC-3 Plus in the appendices of this manual.Note: Other TNC‘s may have different features than the KPC-3 Plus for example, theability to operate two radios at once.
