What is PCISCC-4?

PCISCC-4 is a medium-speed four-port PCI compatible SCC (Serial Communication Controller) plugin card for connection of synchronous serial network devices, typically ham-radio modems. The card is based on the Siemens/Infineon DSCC-4 (PEB-20534H) multi protocol controller ASIC. It supports busmaster-DMA via 10 built-in DMA controllers and descriptor handling. Thus it can work at line speeds up to 52 Mbps. All four SCC cores and HDLC engines can be configured independently from each other. This includes clockmode settings (external/internal RX/TX clocks, DPLL (up to 2 Mbps) etc.) and channel coding (NRZ/NRZI/Manchester/FM0/FM1/CMI). As you can see it is quite flexible as far as configuration is concerned. This is why it is intended for use in PC node controller systems.


Take a look at some commented pictures.

Additional Information

Here is a flyer I made for Weinheim/Mannheim '99. It is only available in German, but also shows a picture and a diagram plus some technical information.

Here is a paper which was presented during the 16th International Packet Radio Convention at Darmstadt Technical University on April 1st/2nd, 2000. This is an English technical paper with a lot of background information. It should answer your remaining questions.

Even more technical information

Here is design information about the project. None of this stuff may be used commercially! You may not sell this documentation or self-made cards built using this stuff, not to other radio amateurs nor to anybody else without my written permission. You may, however build these cards for your own use in amateur radio. Contact me if you have any questions regarding this license.

EAGLE .sch file - schematics
This is the schematic diagram, board revision V1.2. You need at least EAGLE V3.55 to view it. Get a demo version at CadSoft. Newer versions (Eagle 4.x) do not seem to be able to load the files.
EAGLE .brd file - board layout
This is the board layout file, revision V1.2. You need at least EAGLE V3.55 to view it. Get a demo version at CadSoft. ERC and DRC will print warnings and errors, this is normal. Press the "rats nest" button to process the ground polygons after loading.
Notes (text,german)
This is a text file with a lot of notes I sent to two people who wanted to write device drivers. Sorry, German only.
ChangeLog (text,german)
This is a history file documenting the changes since Rev. 1.0
Bill of Material
Here is the BOM. Except for the DSCC-4 and the board there are only standard parts. You can get the voltage regulator as sample from National. Other semiconductor manufacturers sell similar parts.


The reference driver was written for the Linux AX.25 network protocol stack as defined in the paper mentioned above. Since I retired from AX.25 stack maintenance and nobody stepped up to fill the hole this driver is only semi-usable since the last kernel source tree I made was some 2.2.20pre version that is pretty much out of date. No port of neither the stack nor the driver exist for Linux-2.4, but I maintain the driver for the old version here since I feel responsible for providing a reference for future efforts and portage to other platforms.

Current Version: 1.85

A PC/Flexnet and Win32/Flexnet driver has been contributed by Steffen Koehler, DH1DM and can be downloaded from here.


The design is available - in an optimized way - from BAYCOM. Please contact Johannes Kneip, DG3RBU for sales information.


Credits go to:
by Jens David, DG1KJD 2002-06-02