The BayCom EPPFLEX modem
This page provides a brief overview of
the new high speed modem EPPFLEX for the PCs EPP and ECP port.
What is the EPPFLEX modem?
With the first EPP adapter, published in 1997, BayCom made a big leap toward
high speed packet links and network access. The EPP adapter allowed the
connection of a normal DF9IC FSK modem to the enhanced parallel port of
the PC, achieving bitrates of up to 600kbit/s. With the EPPFLEX modem,
which was mainly developed by Thomas Sailer, HB9JNX, BayCom presents a
totally new generation of high speed modems based on the experience with
the EPP adapter.
Basically, the EPPFLEX modem has the same functionality like the EPP
adapter with an FSK modem connected. It integrates all digital functions
of the EPP adapter and the FSK modem in a single FPGA (a XILINX XCS-10),
thus greatly reducing cost of components. The EPPFLEX modem also contains
the analog part of an FSK modem and thus is all one needs (besides of course
a special radio) to go on air with FSK modulation up to several hundert
kbit/s.
Since the FPGA does not have a memory to store its configuration, it
is programmed by the driver when packet operation starts. This has a big
advantage: The FPGA can also be programmed to do something completely different,
by just loading an other driver configuration! In our case, we use the
EPPFLEX also to be used on the PCs ECP port, which allows even higher baudrates.
And there also exists a driver, which allows a perfect emulation of 1200Bd
AFSK, so you can use the EPPFLEX modem also for conventional packet operation.
The EPPFLEX modem allows a great variety of bit rates, for FSK e.g.
from 4800Bd up to about 1Mbit/s (depends on how much data your computer
can still handle!). However, one must decide for a bit rate when building
or ordering the EPPFLEX, since the analog components of the modems have
to be adjusted to this bit rate. But by just changing a few capacitors,
an adaptation to another bit rate can be done late. By default, we deliver
a bit rate of 76.800bit/s, since this has become most popular in Germany.
Other bit rates are available on request.
Where do I get a full
technical information?
We still did not have the time to translate the manual into english,
so our apologies if there is only the german
construction manual available here.
We will work hard to provide an english manual as soon as possible.
However, you can access the circuit diagram
here and also the assembly plan.
Please note that all these technical informations are copyright protected,
we offer it to you for your information and enable you to build an EPPFLEX
of your own, but you are not allowed to use these informations commercially
in any form and you are also not allowed to sell equipment built on the
basis of this technical information!
Which software is available?
Currently, FlexNet is the only software
supporting the EPPFLEX modem. Flexnet drivers and (of course) also Linux
drivers can be accessed here!
The other FlexNet software can be downloaded
from the FlexNet
homepage.
We are currently working to have more
drivers available for the EPP modem. If you are a software author and are
interested to include the EPP modem in your software, please contact the
BayCom team.
What is the status of the project?
The EPP modem is available as of now. A comprehensive
description will be published in the German amateur radio magazine "FUNKAMATEUR"
in the next few months. Please contact baycom@baycom.org
for further information on the EPPFLEX modem.
