SPECIALIZED COMMUNICATIONS

PACKET RADIO

Packet is a unit of data transmitted as a whole from one computer to another, on a network. Packets can be transmitted on radio waves as well as on communications lines. Besides a transceiver and a computer, all you need is a terminal node controller (TNC) or Multimode Communications Processor (MCP). One of the tasks of TNCs and MCPs is to convert data packets to audio tones, and vice versa. This transceiver has a built-in TNC which allows you to use basic (not full) packet applications.

A variety of packet applications developed by hams include packet bulletin board systems (PBBSs). PBBSs are created and maintained by volunteers called System Operators (SysOp). You may access one of your local PBBSs to send e-mail, download files, or obtain various useful information. Thousands of PBBSs, which have formed a worldwide network, relay e-mail to their intended destinations around the world.

PBBS

When you access a local PBBS for the first time, you often need to register as a new user. After you are successfully registered, it will then be available as your home PBBS. E-mail addressed to you will be held under a directory, called a mailbox, on your home PBBS.

To send e-mail, you must designate the address of a recipient, using his or her call sign and the call sign of his or her home PBBS; ex. KD6NUH@KJ6HC. In this example, the e-mail is addressed to KD6NUH whose home PBBS is KJ6HC. If your home PBBS cannot find KJ6HC in its address file to forward your mail, you must designate the address in more detail. You may enter “KD6NUH@KJ6HC.#ABC.CA”, or “KD6NUH@KJ6HC.#ABC.CA.USA”, or up to “KD6NUH@KJ6HC.#ABC.CA.USA.NA”, as necessary. The complete address of a recipient living in the U.S.A., for example, should include an appropriate region code (preceded by a #), state, country, and continent abbreviations, as above.

For further information, consult reference books which should be available at any store that handles Amateur Radio equipment. Web pages relating to Packet will also be helpful. On Internet search engines, use “Packet Radio” as key words to find those Web pages.

Note:

◆Unlike a TNC, a Multimode Communications Processor (MCP) serves as a communications interface in several digital modes such as Packet, RTTY, and AMTOR. You can cause it to switch among the modes by sending a single command from your computer.

◆If there is an amateur radio club in your area, consider becoming a member. You can often learn more in an hour from experienced hobbyists, than in a month of independent research. Ask on the local repeaters, or contact your national amateur radio organization (the ARRL in the U.S.A.) for information on local amateur radio clubs. You’ll be glad you did.

BUILT-IN TNC

This transceiver has a built-in TNC which conforms to the AX.25 protocol. Since the built-in TNC has been designed to work with the Packet Cluster Tune {page 53} and Sky Commander II+ {page 83} functions, some of the enhanced TNC commands may not be available. For the commands supported by the built-in TNC, consult “BUILT-IN TNC COMMAND LIST” starting on page 110. The AX-25 protocol is used for communication between TNCs. The TNC accepts data from your personal computer and assembles it into packets. It then converts those packets to audio tones which the transceiver can transmit. The TNC also takes audio tones from the transceiver, converts them to data for the computer, and checks for errors in the data.

In order to activate the built-in TNC, access Menu No. 55 and select ON. The default is OFF. “PKT” will appear to show that the built-in TNC is ON.

The TNC mainly functions in Command or Converse mode. First, you should learn the difference between these two modes.

•Command mode

When you select Packet mode, the TNC enters Command mode. A “cmd:” prompt appears on the computer screen. You can type commands from the computer keyboard to change the settings of the TNC. When in Converse mode, press [Ctrl]+[C] on the keyboard to return to Command mode.

•Converse mode

The TNC enters this mode when a link with the target station is established. On the computer keyboard, type an appropriate command and a message if necessary, then press [Enter] or [Return]. What you type is converted into packets and transmitted over the air. When in Command mode, type CONVERSE, CONV, or K to enter Converse mode.

Note: The built-in TNC automatically reinitiates when a malfunction is detected; this does not designate that the transceiver is defective.

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