In the paragraphs to follow I will try to cover information related to the equipment and different uses for Packet Radio.
There are many types of Packet Modems (Tnc's) on the market these days. They all have their own special features and when using their own specific software are very effective in getting the job done for the user. Others, in trying to stay with the true Tapr design, will lend themselves to a wide assortment of software to meet the needs of different situations.
Manufactures. There are many different manufactuers of packet modem tnc's (terminal node controllers). There are MFJ, Kantronics, AEA, DRSI and PacComm to name a few.
Kits: Baycom and Tapr (Tucson Area Packet Radio) offer goods kits to build your own packet modem.
I have opted to go with the MFJ tnc's in my shack because of their low price and there true tapr design that lends itself to use with almost any software. The MFJ tnc also lends itself to a variety of different firmware (Eproms). They are easy to modify and have ample room inside the case to work. Over the years MFJ has been ready with the latest upgrade kits as they were needed to keep pace with the changing face of packet radio. This includes the latest PBBS (mailbox) firmware and memory expansion kits as well as high-speed modems and other equipment to make the experience complete.
Nodes. The KPC (Kantronics) family of packet modems have K-nodes built into their modem firmware so as to incorporate a node along with it's other many features. Other types of tnc's accomplish this through special software or specialized Eproms that provide highly sophisticated networking systems like The-Net or The Rose Switch. The best thing about getting the job done with Eraseable Eproms is that you can make your packet modem do the work while being a stand-alone device.
Digipeaters. All MFJ tnc's use digipeaters to retransmit data. They use a store and forward method to move information. They are not nearly as friendly because, unlike a Node, they have a tendency to capture the frequency and make everyone else wait. With digipeaters you are limited to 9 consecutive links. With nodes there is no limit and a consistant connection is maintained between all repeating stations.
Software. There are many kinds of software programs for packet radio. Depending on what you hope to accomplish there is software to do almost any task that you might need if you want to leave your computer running 24 hours a day. The software, because of the capacity of the computers memory, can be a lot more elaborate.
BBS Systems. There are many different BBS programs available to be used for packet these days. It is mostly a matter of the equipment that you intend to dedicate to your hobby. Are you going to be using a old IBM XT with limited memory or something a lttle newer like a 486 or Pentium with some serious memory and hard drive space? Msys, Jnos, Wnos and Worli are just a few.
Automatic Packet Reporting System. This is a system where a group of stations broadcast AX.25 beacons giving regular updates of their locations from GPS or other sources of information. There are programs that will allow the decoding of these specially formatted beacons and display the location of the stations on a map.