Subj : Todays New Gear Tip
To   : All
From : Daryl Stout
Date : Wed Sep 13 2017 12:06 am

Digital Modes 

Exchanging text, email, graphics, and files is an important part of
today's emcomm and other applications of radio. The modes that transmit
and receive data are referred to as digital modes. On VHF and UHF, the
most common digital mode is packet radio or "packet".

(tapr.org/packetradio.html)

The name comes from data being transmitted in groups of characters that
are called packets. Packet is also known as AX.25, the designator of
the technical standard that describes it. To use packet, you'll need
an FM radio, a special interface called a terminal node controller (TNC), 
and a computer as shown in Figure 6. Some radios have TNCs built in. 

Packet provides "keyboard-to-keyboard" communication a bit like instant
messaging. It is also used to send email from your computer via Winlink
system mailboxes.

The Automatic Position Reporting System (APRS -www.aprs.org) uses packet
radio to report your position and other information over the Internet.
A few radios have features designed for use with APRS, such as special
text displays, a data interface to communicate with a GPS receiver, or
built-in GPS receivers.

Packet commonly operates at two speeds; 1200 bits/second (bps) and 9600
bps (about 120 and 960 characters/second, respectively). At the slower
speed, the TNC converts characters from the computer's serial or USB port