USB to 9pinD serial adapters?
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From: T i m on 13 Feb 2010 09:28 On Sat, 13 Feb 2010 12:54:02 +0000, peterd.news(a)gmail.invalid (Pd) wrote: >> It wasn't 'damned stuff', it was something that you often needed to >> understand to make work properly / first time. > >I used the TRS-80 and Commodore 64 to communicate with cash registers in >the early 80s over RS232, never had any problems either locally or >through blinding fast 1200bps modems. ;-) (Maybe we are made of sterner stuff) > The C64 was great because the >Basic commands for controlling the RS232 port were simple but gave you >complete control, so if the other end was a bit slow to respond it was >easy to adjust wait times or buffer read times. Handy. > >Perhaps it was my lack of experience that meant I wasn't looking for >problems. Indeed [1] >It seemed pretty straightforward that if you were connecting >to a modem the wires were straight through, and if going locally the >pairs of data and handshake wires needed to be crossed over, either in >the cable or with a converter. Yup, that was pretty well it in many many of the cases. I would turn up to a customers premises bearing a 24 port StatMux and was presented with a bunch of cables hanging out of a slot in a comms cabinet. I see they are DB25M and see they are coming from a comms card or host of some sort. A quick check with the Break-out-box shows DTR and RTS (typically confirming a DTE) and I know the ports on my Mux are DCE's by default. Plug and screw / clip lock em in (no locks on USB stuff in general <g>) plug my Laptop (or customers dumb terminal if handy) in and configure the port speeds, byte length, parity, flow control, and any other characteristics the install requires we are away. Simples. ;-) > >[...] >> >Ah - those were the days! >> >> They were, and why I remember them fondly. Sfunny though, 'wiring' >> still continues to cause people problems. Like the 100 Ethernet cables >> I diagnosed as faulty and that had to be re-wired (they hadn't >> observed the parings) > >I hope that wasn't my work. I don't think so. ;-) > I got a job laying Cat5 cable throughout a >North London college before I really knew what I was doing. Ah, this was a central London training centre and they really should have known better. > Just got >given a couple of reels of cable, a few bags of connectors and a >crimping tool. No radio? > One of the connector bags had a piece of paper in it >showing possible variations of pairings - I chose one fairly arbitrarily >and made up all the cables assuming any crossovers would happen either >in the patch panels or routers. AS long as you took pins 1 and 2 at one end as a pair and to the same at the other and did the same with 3 and 6 you should have been ok. ;-) >The whole network seemed to work Ah, the network I mentioned 'worked' but only over short runs. > and I >got paid after the students were back hammering the servers, so I guess >nothing too bad showed up. If it had completely failed due to my >ignorance of which pairings to use I wouldn't have been surprised. Hehe. Another one I resolved because of experience and knowing the rules was re a short thin_ Ethernet patch lead between two multi-port repeaters. The repeaters had been swapped and replaced and various 'experts' had looked at it to no avail. I spotted a very tidy but probably too short lead between two repeaters, swapped it out for a 1m one and all was fine and dandy. ;-) You wouldn't think someone could make a mistake with just two conductors eh! Cheers, T i m
From: T i m on 13 Feb 2010 09:30 On Sat, 13 Feb 2010 14:16:44 +0000, usenet(a)alienrat.co.uk (Woody) wrote: >> I also had one and had similar issues when trying to connect it to std >> stuff because of it's not std ness. Anything that didn't have an >> industry std spec (serial) interface is also likely to be an issue >> (but rarely insurmountable if you had the right kit and experience). > >Ironically i never had a problem with a mac to RS232 connection, I had a >couple of leads I made at work that did everything and an RS232 breakout >box. I did have a problem with a ratheon radar rs422 connection to a >radar processing unit, and had to make an interface to connect the two, >which is harder than it sounds as I was in africa at the time, and the >electronics shops are a bit different from ours. So you had to whittle one? ;-) Cheers, T i m
From: Woody on 13 Feb 2010 17:43 T i m <news(a)spaced.me.uk> wrote: > On Sat, 13 Feb 2010 14:16:44 +0000, usenet(a)alienrat.co.uk (Woody) > wrote: > > > >> I also had one and had similar issues when trying to connect it to std > >> stuff because of it's not std ness. Anything that didn't have an > >> industry std spec (serial) interface is also likely to be an issue > >> (but rarely insurmountable if you had the right kit and experience). > > > >Ironically i never had a problem with a mac to RS232 connection, I had a > >couple of leads I made at work that did everything and an RS232 breakout > >box. I did have a problem with a ratheon radar rs422 connection to a > >radar processing unit, and had to make an interface to connect the two, > >which is harder than it sounds as I was in africa at the time, and the > >electronics shops are a bit different from ours. > > So you had to whittle one? ;-) No, you go into a shop, ask for a transistor by model. They say they don't really work with model numbers, so you ask for NPN, half watt, hfe > 100, TO18. They smile and call to a guy in the back room and the guy looks round, brings you some transistors, they test them and give them to you (they are obviously second hand). The back room is full of broken radios, phones, tvs etc, with a group of people desoldering componants. Its a slightly different world, but it seemed to work fine when you are used to it! -- Woody www.alienrat.com
From: T i m on 13 Feb 2010 18:16 On Sat, 13 Feb 2010 22:43:46 +0000, usenet(a)alienrat.co.uk (Woody) wrote: >> So you had to whittle one? ;-) > >No, you go into a shop, ask for a transistor by model. They say they >don't really work with model numbers, so you ask for NPN, half watt, hfe >> 100, TO18. They smile and call to a guy in the back room and the guy >looks round, brings you some transistors, they test them and give them >to you (they are obviously second hand). The back room is full of broken >radios, phones, tvs etc, with a group of people desoldering componants. The ultimate recycling then. > >Its a slightly different world, but it seemed to work fine when you are >used to it! Like watching them pull the head of an old Merc and rebuild it with bits robbed off other old Mercs and with few decent tools (and certainly no 4 post lift nor Suntune unit) and get it running for next to nowt. Not a lot different from our breakers I suppose, other than the prices and the amount of effort they are willing to put into retrieving stuff. ;-) Cheers, T i m p.s. On a similar vein I'm playing with several old PC's (gonna build me a WHS) and it's nice to be able to swap so much about. 20W for a T-20 Thinkpad solution and 55W for an old Sempron 2600+ (4 x SATA II) .. The Atom330 has Gb Ethernet but only 2 x SATA. <sigh>
From: Woody on 13 Feb 2010 19:00
T i m <news(a)spaced.me.uk> wrote: > On Sat, 13 Feb 2010 22:43:46 +0000, usenet(a)alienrat.co.uk (Woody) > wrote: > > >> So you had to whittle one? ;-) > > > >No, you go into a shop, ask for a transistor by model. They say they > >don't really work with model numbers, so you ask for NPN, half watt, hfe > >> 100, TO18. They smile and call to a guy in the back room and the guy > >looks round, brings you some transistors, they test them and give them > >to you (they are obviously second hand). The back room is full of broken > >radios, phones, tvs etc, with a group of people desoldering componants. > > The ultimate recycling then. That is what it is. It is nice to see it being used, and I was gratefull that a long way up a mountain in kenya I could actually get electronic components at all. > >Its a slightly different world, but it seemed to work fine when you are > >used to it! > > Like watching them pull the head of an old Merc and rebuild it with > bits robbed off other old Mercs and with few decent tools (and > certainly no 4 post lift nor Suntune unit) and get it running for next > to nowt. > > Not a lot different from our breakers I suppose, other than the prices > and the amount of effort they are willing to put into retrieving > stuff. ;-) Yes, pretty well -- Woody www.alienrat.com |