Protocol Tunneling
Maitland Bottoms
aa4hs@amrad.org
Wed, 1 Apr 1998 10:47:39 -0500 (EST)
Hello Tacos,
Interesting news on the digital networking front. Though some of you
will probably hear about this from other sources, it seems timely for
me to forward it along to Tacos today.
-Maitland
Announcement Follows:
Subject: Announcement: TCP/IP over Morse driver released
Author: sfraser@sierra.apana.org.au (Steve Fraser) at Internet
Date: 4/1/98 7:24 AM
To reinforce the modern ham's preoccupation with Morse Code, and because
Morse Code is still a requirement for unlimited access to HF bands, a new
driver for Linux has been released, that carries TCP/IP over Morse Code
(TOMC). The driver is fully compatible with existing Linux network software
and utilities.
How Does it Function?
TOMC sends binary-encoded-morse (BEM) to and from a serial port of a
computer. In hardware terms, the DTR line is toggled to key the transmitter
(via a very simple circuit - a resistor connected to the base of a power
switching transistor, which keys the rig in CW mode), and the CTS line is
fed with from a hard-limiting op-amp which is in turn fed from the rig's
speaker for receiving). This is very similar to the "Hamcomm" and similar
devices.
In terms of software, each binary bit is encoded as the repective morse code
for a zero or one respectively - although a "fast" mode is possible whereby
zeros are send as "E" and ones are sent as "I". CW users will recognise this
as one or two dits respectively.
How Well Does It Work?
Recent tests have shown that TOMC using BEM is capable of outperforming most
human operators in sending of text files (using ftp transfers). Of course,
human operators cannot send graphics or binary files with morse, whereas
TOMC can, so no meaningful comparison is possible here.
In noisy conditions TOMC can easily outperform AX25 packet operations, thus
reinforcing the need for amateurs to continue to use morse code.
How Is It Configured?
TOMC comes with a simple configure program:
morseattach [-d] [-f] ser_device ax25_portname
[-d] is used for debugging, and displays the CW dits on the screen
[-f] is "fast mode" -see above. If a "fast mode" TCP/IP arp is received by a
station not in fast mode (or vice versa) the driver will temporarily switch
modes to match the incoming arp request, and continue in that mode for the
remainder of the connection. The other parameters are:
ser-device is the serial device used (/dev/cua00 etc)
ax25_portname is the port name from the /etc/ax25/axports file which will
be mapped to this device (many people use ax0, ax1 etc)
The kernel IP and TCP stack will automatically use the driver, and normal
TCP/IP routing etc must be configured (in exactly the usual way) for this
port as it is for all other ports. The file consists of a series of kernel
patches, under the GPL licence.
Is it Legal?
The use of this mode may not be legal in all countries. I'd suggest
contacting your local regulatory authority and asking them about it before
using it. You may need to explain the mode to them. As it is "pure" morse I
do not expect too many problems.
Where Do I Get It?
A server for anonymous ftp has been set up (but the DNS entries have not yet
been done) so you'll have to use its IP number.
Just do:
ftp 127.0.0.1
(log in as anonymous)
cd /tmp
get TOMC.1.4.98.tar.gz
(if it's not there yet try again in a few days)
Problem Reports.
If you encounter any problems, please email the maintainer:
Apr.Fule@localhost
73
Steve