Magic smoke is generally released by : 1) Overvoltage on one or more pins (e.g. connecting an RS232 signal to a TTL input) 2) Reversing power lines 3) Shorting TTL outputs together (although this may not do any damage if you're lucky) Since the PS/2 keyboard and mouse interfaces are electrically very similar, I can see no reason why you'd let the smoke out if you pluged them into each otehrs' conenctors, unless oyu plug a PS/2 keyboard into one of thsoe seiral pouse adapaters and then into an RS232 port. But that's a PS/2 interface, it's an adapter for a mouse that can either be PS/2 or RS232. Plugging a true PS/2(only) mouse into such and adapter would do damage too. I am suprised nobody has complained yet that IBM used a DB25 socket for a TTL-level parallel port. After all, plugging an RS232 cable in there will do a lot of damage. Or that HP used a 50 pin Microribbon connector for an RS232 port on some of their machines -- and evenbrought the sysem power lines (+5V, +12V, -12V) out on it. Connecting a SCSI device to that will not be pretty! I guess it may come down to the unix philosophy in the end. 'We don't stop you doing stuping things becuase that would stop you doing clever thigns too'. There may very goof reasons for wanting to connect a device to an interface connecotr the manufacturers didn;t think of... Of course no sane person uses mains connectors for anything but mains. Note I said 'sane'. There was at least one UK audio amplifier (I think it was a Pye) that used the same type connector -- a 2 pin Bulgin thing -- for both mains input and loudspeaker output. Swap them round, and you needed a new output transfdormer. I also once had to repair an infrared spectrometer where the manufacturers had used such a Bulgin mains connector for the analogue output signal. There was no other mains connector on the electronics box, so the operator had, not suprisingly, connected mains to that. In factm the electronics got its mains supply down a multi-core cable (also carrying motor control signals, etc) from the optical unit (which did have a mains cable). Needless to say applying mains ot the output let some smoke out (but suprisingly lttle -- I think one resistor was burnt out). Hmmm... I can see both sides to this. On the one hand, it's a very bad idea to use the wrong PSU ('wrong' in voltage, or polarity, or...). So having unique connectors that only fit the right device would seem to be beneficial. But ther other side is that wall-wrts get sepearated from the devices the power. They may fail. And they're often mains-voltage-specific (a problem for Europeans wanting to use US stuff...). Some years ago, I bought one of those packs from Maplin of the 16 most common power connector 'tips' and a cable with a moudled socket on the end to take them. The other end of the cable I wired to a couple of 4mm plugs to fit my bench supply. THis has proved invaluable over the years for powering up units where the original wall-wart is missing or can't be used. So I can see the beenfit of a stanard connector too, one that I can match up with one from this kit. Also, wall warts fail. Often the output cable fractures internally, close to the moulded connector. If you can't get the connector, you may be stuck trying to get a new wall-wart. Try that for a 20 year old unit sometime :-) On the whole, I guess I'm in favour of standard connectors (2.1mm coaxial, 2.5mm coasial, maybe 2.5mm and 3.5mm jack plugs), but giving the power requerements and polarity on the unit iteslf somewhere (either on the nameplate label, or on the silkscreen of the PCB inside, or...). Not in the manual only, as that can get lost too. How pointless, consdiering how rarely most people need to set up a new computer, compared to doing other things with it. It's similar to the 'easy to learn' claims of a lot of products. I don't much care about that. What I want to know is whether, once I've leart to use it, will it save me time/effort/whatever. I am quite prepared to take time to learn something that will, and equally, won't waste any time at all on somethign that won't. Incidetally, I was once timed to see how long it would take me to dismantle an ASR33 into the main sections (cover, base pan, typing unit, keyboard, punch, reader, call control unit) and put them back together again. I think I got it down to under 5 minutes in each case. -tony

Oh mo, it's not one of the _modern_ standard mains connectors. Bulgin make/made a large variety of connectors along with things like fuseholders, switches, knobs, etc. I probably have an old enough catalouge somewhere to get the exact part number, but %deity knows where said catalogue is :-) I am not sure if theyr were ever used outside the UK (but the 3 pin versionswere very common as mains connectors in the 1950s/1960s here). I can't think of any classic-computer related device that used them. Anyway, the connectors I am thinking of were part of as series. They were circular, most of them were chassis mouting plugs and cable sockets. The plug was recessed into the panel, and the socket part fitted into it. There were 1.5A and 5A versions with 2, 3, or 6 pins. Polaraision was acheaived by a groove down the side of the socket part and a corresponding ridge in the recessed plug. In many cases the wire terminals on the socket part were covered by a simple screw-on cap which means they're not not approved for use above 50V (since you can unscrew said cap and get access to live parts without the use of a tool). There were later mocels of some of the sockets with the cover held on by screws, AFAIK those are still OK for mains use. If you like I can tey to find the part numbers for them. -tony

On 15 Sep 2007 at 23:40, Tony Duell wrote: I said - No, but I didn't specify that I meant the keyboard and mouse ports (though there was some chatter about it. My concern is with things such as printer and RS232 ports using the same connector, or putting power on connector pins where it's possible to insert the connector "upside down". Or using a power connector and wiring it differently than the rest of the world (e.g. MD2 diskette drives as opposed to anyone's 3.5" diskette drive). I believe that a few old Calcomp 8" floppies actually put mains power through the signal connector on a couple of models. Wall warts are perhaps the worst examples of "user friendly" design. It's not sufficient that one match the voltage and current and AC vs. DC but one must also match the polarity. And the markings on some equipment is missing entirely or engraved/printed too small to see clearly. I've seen those little "tip and ring" symbols in all 4 possible orientations. Take a look at a dozen bits of equipment with wall warts and you'll note that many carry an entirely different branding than the equipment they power. So matching brands won't work. And even when there are matching brands, there's no specific information that a Sony CD player PSU belongs to the CD player and not the DAT drive sitting next to it. And so on. I have several of those "universal" wall warts and find them to be useful also. I also keep a doublet (magnifier) handy for deciphering those connector symbols. Cheers, Chuck

That's why I **always** label the wall wart of anything I buy new or used. I have a tray here with all of them, and I can find which is which in a second, just reading the labels I made. About the protection, it is inexcusable, but think: The manufacturer assumes you'll use the wart he sold you :) It's up to you to get confused and use another :o) And btw, they need to sell more new units :oD Greetz Alexandre

looked like loads of phun Alexandre. I thought the black MSX 2+ tower was psyk. I like that Sony unit too. In fact I want 1 or more. --- Alexandre Souza <alexandre-listas at e-secure.com.br> wrote: http://www.flickr.com/photos/29379227 at N00/sets/72157601958420285/ ____________________________________________________________________________________ Got a little couch potato? Check out fun summer activities for kids. http://search.yahoo.com/search?fr=oni_on_mail&p=summer+activities+for+k…

Tony Duell wrote: You got me curious, so I just ran a search on Farnell's database for DB25 connectors rated to 500V; it coughed up 60 different ones. I can't think of an example where I've actually seen it done with D-types, but I've certainly come across it on telecomms stuff before using DIL-type card connectors (what I've always called 'euroconnectors', but I'm not sure what the official term is) It always looks a bit worrying to be running mains type voltages over that sort of thing, but I expect it's well within the limits of most parts. [wall warts] I bought one of those wall warts with a range of interchangeable connectors when I was in the US last. Seemed like a good idea at the time; the connectors were reversible so that you could swap polarity just by changing the connector through 180 degrees on the cable, not to mention that it came with about ten different sizes of connector. (the kids were getting through batteries in toys with lightning speed :-) It was only when I took the packaging off that I discovered the flaw: the terminals at the end of the cable are marked for polarity - but there are *no* markings on the interchangeable connectors which give an indication of which of the two pins goes to the connector's ring, and which goes to the tip. Without any test gear it's random as to the polarity of the plugged-in connector.