This page provides a brief overview of the new high speed interface for the Enhanced Parallel
Port (EPP).
The EPP adapter is an interface between the EPP port of a PC and a DF9IC high speed modem.
It mainly targets the new German 70cm wideband access channels with a baudrate of 76.800 kBd.
However, it can be operated at other baudrates between 9600Bd and 307kBd, too. These baudrates
cannot be achieved using conventional Centronics ports or RS-232 technology.
The EPP modem is
a joint development of Henning, DF9IC (idea and first prototype), Gunter, DK7WJ
(software driver and extensive testing) and Johannes, DG3RBU (final implementation,
board design).
The following image shows a block diagram of a packet station with the EPP and its
interfaces to modem and PC.
The EPP adapter mainly consists of the interface logic to the EPP and two IDT FIFOs of
2kByte size and integrated parallel serial converters. For the receiver,
data is clocked
into the RX-FIFO, where it can be read via normal EPP read operations. For TX,
the data
is written as 8 parallel bits into a TX FIFO, from where it is read sequentially by the
modem connected to the EPP adapter.
Where do I get a full manual?
Here! Click here for the English manual (PDF-format, 100kbyte), or click here for the German manual (PDF-format, 100kbyte). You will also need the circuit diagram of the EPP adapter (in GIF format) or the circuit diagram in PDF format. You can display PDF files with the acrobat reader.
The EPP adapter fits on a 80*100mm PCB. Click here
for the component placement diagram
The following image shows a photo of the EPP board.
On the right side, you can see the 25p. connector to the EPP port. The
pinhead connector on the left side of the PCB directly connects to a
DF9IC compatible FSK modem. There are
also 4 status LEDs signaling PTT, DCD, Connect and Data available (STA).
Together with a DF9IC modem, the EPP-modem combination fits into a standard
Euro size case:
Currently, FlexNet is the only software supporting the EPP
modem. The software can be downloaded from the FlexNet homepage.
The EPP driver will be on the FlexNet site soon. With its modular interfaces,
FlexNet permits a combination of various hardware drivers and terminal
frontends such as the BayCom terminal (BCT) or host mode software.
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.
The EPP modem is available as of now. A comprehensive description has also been
published in the German amateur radio magazine "FUNKAMATEUR" in 1998. A DF9IC
modem capable of speeds up to 600kbps is also available from BayCom. Please contact baycom@baycom.org for further
information on the EPP and the new modem.
