The Building Blocks
A packet network is built from a few kinds of station, often combined in one box.
- Digipeater: a station that hears a packet and sends it on again on the same frequency, extending range. APRS relies on them.
- Node: a network station that links to other nodes, often on separate frequencies or links, and passes your connection along. You connect to your local node, then ask it to connect you onward.
- BBS: a bulletin board system, a mailbox that stores messages and bulletins and forwards mail to other BBSs automatically.
- Personal mailbox: many TNCs have a small built-in mailbox so others can leave you messages while you are away.
How Mail Finds Its Way
Packet mail is addressed like postal mail, from the specific to the general: the ham’s callsign, the BBS where they collect mail, then region, state, country and continent. Each BBS knows which neighbor to hand a message to, and messages hop along, sometimes over hours, until they arrive.
Bulletins work the same way but go to many BBSs at once, for club news, technical notes and, in emergencies, official traffic.
The Software
These are widely used and actively maintained; check each project’s own site for current versions.
- BPQ32 and LinBPQ: node, BBS and chat server in one, for Windows (BPQ32) and Linux including the Raspberry Pi (LinBPQ). The most common choice for running a node today.
- JNOS: a long-running package that carries internet-style networking (TCP/IP) over packet, with a BBS and mail.
- Direwolf: the software TNC, which can also run as a digipeater. Often the radio end of a LinBPQ node.
- Outpost: a Windows message program built for emergency communications groups, which handles BBS mail and standard message forms.
Packet and Emergency Communications
Because packet needs no internet and no phone lines, many ARES and other emergency groups keep packet and Winlink stations ready. Typed messages arrive exactly as sent, which matters for lists of names, supplies and addresses that are easy to garble by voice.