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Surfin’: Moving Packets with DDP

04/29/2011

By Stan Horzepa, WA1LOU
Contributing Editor

This week, Surfin’ looks at a new protocol for moving packets through the ether.

Danny Knaggs, 2E0DPK, is designing and developing a new free, open source ham radio protocol called “DDP” -- for “Danny’s Digital Packet” -- that provides a modern alternative to the existing packet radio protocol. Transmitted and received packets are “in plain text so they can be seen by eye (on the waterfall, console, etc.) and for ease of use and implementation.”

Like any other communications protocol, DDP requires “modulation” to move its packets. fldigi and RS-232 provide the back end for DDP to move its packets. By default, DDP uses PSK500R, but it can run on any other PSK mode, too. And using RS-232, you can build your own modems suitable for the application. Knaggs has designed and built two different DDP-suitable modems: an 1800-baud AFSK modem and a 9600-baud GMSK modem.

Danny used Python to write DDP, so it should run on any operating system that supports the Python executable without modification including, but not limited to FreeBSD, Linux and Windows

  • DDP already includes some applications including:
  • BBS server and client apps just like the old bulletin boards
  • EmComm sends and forwards messages to other organizations during emergencies
  • File transfer app to send and receive files with other users
  • HTTP proxy server and client app to browse the Internet via RF
  • IM chat app to send and receive “instant” messages with other users
  • Repeater app that transparently repeats packets for cross-banding or plain-vanilla repeating

Visit the DDP website for more information and downloading.

Until next time, keep on surfin’!

Editor’s note: Stan Horzepa, WA1LOU, remembers when packet radio was a modern alternative to radioteletype. To contact Stan, send e-mail or add comments to the WA1LOU blog.



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