Hi I am designing an ECB bus backplane for my N8VEM SBC project and am looking for some peer review prior to going to manufacturing of these PCBs. The N8VEM SBC seems to be working out alright. About a half dozen people have successfully built the SBC so now it is time to start thinking about peripheral expansion. Although the N8VEM SBC uses the ECB bus for expansion, I have not ever used ECB bus machines as they are common in Europe but extremely rare in the US. I have made an ECB bus backplane prototype using prototype boards and it works well enough so I think the basic concept is sound. However, I would like to make this ECB backplane as common and general as possible so other hobbyists can use it not just N8VEM SBC builders. I would really like to avoid any inadvertent N8VEM unique extensions. If you have experience with ECB bus based machines, I would like to hear your comments and suggestions. So far, the ECB bus backplane has six DIN 41612 connectors. All 96 pins are routed. Pins for IEI/IEO have jumper pads per connector to allow usage of Zilog peripheral interrupt priority scheme. The backplane has its own Vcc and Gnd, including a power switch and LED power indicator. The PCB is 2 layer to keep costs low. Each side has a ground fill zone for a low impedance ground. I will be using the double thick PCB material (3.2 mm) for rigidity and the double weight copper trace for low impedance. Vcc and ground traces are triple wide (51 mils) minimum and also routed on both the component and copper sides of the board. The rest of the traces are the usual 17 mils wide. After I order some of these backplanes, I will make them available in a similar fashion as the N8VEM SBC. The PCBs will be available for $20 each plus shipping. The builder will have to source the rest of the parts. If you are interested in helping or have questions, please review the PCB backplane design at: http://groups.google.com/group/n8vem/files?&sort=rdate There are two recently uploaded PDF files containing the schematic and the PCB layout. Thanks in advance for any *constructive* feedback. Have a nice day! Andrew Lynch