TNC with modem firmware
Introduction
The objective of this project is to make a TNC behave like
a telephone modem. Therefore it must be possible to 'dial in'
to the modem using a standard SLIP or PPP connection.
However, using a point-to-point protocol in a
point-to-multipoint environment (radio frequency) would
eventually cause unforeseen problems. Additionally HAMs
should communicate AX.25 on the frequency.
The trick is to implement a bridge inside the TNC. The
bridge can offer the correct data link protocol to the
corresponding device, either PC or transceiver.
HAMs can take advantage from this method,
because it allows us to communicate over the radio as we are
used to over the Internet using TCP/IP or other user friendly
networking protocols.
Using this kind of TNC's encourages us into
using servers which provides services that are identical to
those on the Internet. That should not really be an obstacle
as ON1BLU (Gert Leunen)
clarified on his website.
Implementation
The idea was implemented into the MCB152, a
microcontroller based on an MCS51 derivate, design by ON4AWM (Walter Machiels).
Everything is written in assembly language.
The initial, fully working versions are SLIP
implementations which provide AX.25 UI connections in the
air. These versions offer half duplex connections for Baycom modems for USCC
cards.
Currently I am working on an extended version which should
offer a full AX.25 v2.2 implementation, SLIP, PPP and a large
variety of test modes.
Anyone interested on information about the sourcecode or
willing to help programming is welcome to contact me
personally.
Download sources
SLIP sources
release info, general include files
slip v1.0.zip, slip v1.0a.zip, slip v1.1.zip, slip v2.01.zip, slip v2.02.zip, slip v2.0a.zip
New implementation
most recent
Download HEX files
slip30.hex
Related links
Contact me
Joachim Elen
Naamsesteenweg 333
B3800 Sint-Truiden
België.
TEL: +32 11 674426
Acesses
since september 2001
