On Wed, 01 Dec 1999, you wrote:
> Kantronics KPC-2400 used QAM and was regularly used to
> modulate FM transmitters. I don't even know of anyone ever
> successfully using it through a linear transmitter. I remember
> it well as it was the last modem I did for AEA for the DSP-x232
> box. It is V.26B tones and a royal pain in the butt.
>
> Bob
>
Now thats interesting....
I've been using ex British Telecom 4th generation modems type 4241x for a
couple of years on a 70MHz link at 2400bps. These are 4 wire modems (leased
line) that use V26B tones with V27ter scrambling, dibit encoding the 2k4 at
1200baud. Using a variety of phase and FM modulated radios, they have all worked
extremely well (and within a 10KHz channel) - very short training time and the
interface is a simple VOX switch operated by the TX audio keyed by running them
in half duplex using RTS as the turnround signal.
The interface is either an SCC card, a home brew KISS only TNC or a modded
version of the DOS Baycom TSR ax25.com which outputs a bit rate TX clock on the
TXd line.
If anyone in the UK is interested, I've still got 20-30 left (I dumped over 300
of them)
--
73 de Robin. G8ECJ Hub manager gb7ipd
NTS: G8ECJ@GB7TVG.#42.GBR.EU AmprNet: [EMAIL PROTECTED]
Internet: [EMAIL PROTECTED] http://www.gb7ipd.freeserve.co.uk/
Shack: (+44) 1628 533311 Fax: (+44) 1628 850165
Club pages (g4xyw modem etc) at http://www.tvipug.freeserve.co.uk
