Subject: Re: Apple 2 Custom hardware Path: lobby!newstf02.news.aol.com!portc01.blue.aol.com!news.maxwell.syr.edu!newsfeed.cwix.com!cyclone.southeast.rr.com!typhoon.southeast.rr.com.POSTED!not-for-mail Message-ID: <3972A4F8.FA174F29@jb.saic.com> From: Scott Sidley Reply-To: sidleyr@jb.saic.com X-Mailer: Mozilla 4.7 [en] (Win95; U) X-Accept-Language: en MIME-Version: 1.0 Newsgroups: comp.sys.apple2.programmer References: <8klklb$9ov$1@nnrp1.deja.com> <8knoug$rel$1@nnrp1.deja.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 43 Date: Mon, 17 Jul 2000 06:11:50 GMT NNTP-Posting-Host: 24.28.214.161 X-Complaints-To: abuse@rr.com X-Trace: typhoon.southeast.rr.com 963814310 24.28.214.161 (Mon, 17 Jul 2000 02:11:50 EDT) NNTP-Posting-Date: Mon, 17 Jul 2000 02:11:50 EDT Organization: RoadRunner - Cox **** **** wrote: > Thank you, even URL's are a big help. > Yes, it wouldn't be a very complicated card. The components aren't that > > do. What bothers me the most, is that we won't want the rj45 jack direct on > the pcb, because even if the bus slot lines up with the back panel > correctly, increases pcb greatly, and the pcb could end up being the > costliest component. So we do like 90% of other apple cards, use a cable > that connects to the back panel jack... but what kind? I'm afraid that a > ribbon cable is going to be too noisy even for 10mps ethernet, can we just > solder solic core cat5 to the pcb? And why not? Also, even if this works, > the rj45 jack I've found is designed to be soldered to a circuit board, but > its cheap. Do we have another yet smaller pcb for the jack? Do we go with > those like in wallplates, where they are designed to connect directly to > cat5? they won't fit correctly, and carry a $5 a piece price tag. I'm a > hobbyist, not an electrical engineer, so if anyone wants to laugh at me, go > ahead, but these are how I see things, and suggestions are most welcome. > ****.****, You should use a 10 pin header with a ribbon cable to a DB9 connector, mounting the DB9 on the back panel in one of the small cutouts. Then use a standard DB9 to RJ-45 adapter (telco standard EIA568B mappings) to get to the RJ-45. On the header you only need 4 wires for the Ethernet (TX+, TX-, RX+, RX-) the other 6 should be grounds to add a small amout of shielding. Most Apple // users can handle that setup, and it removes the RJ-45 from the PCB. Its also fairly robust, allows quick removal of the card and you can buy the cable premade (10s of millions of pc motherboard use them for Serial ports) for about a $1.00. You can get the DB9-RJ-45 adapters for about $4.00. BTW unaccelerated Apple //'s will probably be limited to 25K bytes/sec burst I/O, so a fairly large buffer may be required, unless you are planning to add a cpu or sequencer and do burst DMA. I would look into bank switching the packet buffer memory via slot I/O or maybe even make it a RAMDISK card.