Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!erd From: erd@tut.cis.ohio-state.edu (Ethan R. Dicks) Newsgroups: comp.sys.amiga Subject: Re: New Serial Port Board (Less Expensive) Message-ID: <36918@tut.cis.ohio-state.edu> Date: 24 Feb 89 15:55:59 GMT References: <503@madnix.UUCP> Reply-To: Ethan R. Dicks Organization: Ohio State University Computer and Information Science Lines: 54 In article bader+@andrew.cmu.edu (Miles Bader) writes: >perry@madnix.UUCP (Perry Kivolowitz) writes: >> The board contains two independent serial ports which can be programmed for >> operation at up to 78.6KBaud. The board (which fits in a single slot >> including rear connector mounting) comes out with 2 DB-9 ``AT'' compatible >> ports which include: > >This sounds all very nice, but... why are you using connectors that >are incompatible with what the amiga's serial port uses? I'm tired of >making strange adaptor cables! > >-Miles Notice how he said "single slot including read mounting." Measure the width of a DB-25 connector head and compare twice that value (plus some intervening space for mechanical stability) with the height of the metal bracket on A2000 slots. Ta Da... Two DB-25s won't fit comfortably on one of those brackets. The cable solution he proposes is not "odd." Why do you think C-A changed the serial connector for the A2000 and A500? To allow Amiga users to hook things up with "industry standard cables." (newspeak for IBM compatible ;-) Notice how Perry then mentions that the DB-9 connectors are "AT" compatible.... Ta Da... Still "IBM compatible," although a different standard. The only reason wh have been using DB-25 connectors for RS-232 is because we have been using them for years. The original Macs used DB-9s, and now use DIN-8s. Some of DEC's equipment uses DB-9 and DB-15 connectors for use with a special cable (the other end has a DB-25) Even Ataris use a funny RS-232 connector on the machine. The overall reason these odd connectors are being used is to save I/O panel space. When you are cramping multiple connectors onto a small bulkhead, you need to use small connectors. Since RS-232 has lots of pins which are defined but rarely used, most designers use a common subset of signals, allowing the connectors to be non-standard. About the only other option Perry has is to use up two I/O slots with his card. How many people who have a Bridgeboard also have spare slots? I can't see him cutting down a potential market. Since you have to buy additional cables anyway, you might as well buy the ones that work. In closing (to a reply which has grown far longer than intended), I would like to repeat my support to Perry and ASDG, and to say that I don't think the DB-9s are a hinderance. The only recomendation I might have is that one have been a DB-25 and the other a DB-9. Since the board is already built, there is no reason to change it. -ethan -- Ethan R. Dicks | ###### This signifies that the poster is a member in Software Results Corp| ## good sitting of Inertia House: Bodies at rest. 940 Freeway Drive N. | ## Columbus OH 43229 | ###### "You get it, you're closer.