Hi Bruce For RS-232 by far the easiest way to do it is order some of these: http://www.ebay.co.uk/itm/2PCS-High-Compatiablity-USB-to-232-RS232-Adaptor-Converter-PL-2303HX-MAX232-/271358227870. I've ordered a few, they work well.
There are other types but if it's definitely RS-232 you're using then make sure it has a MAX232 or similar chip on them, because (as iyaoshi says) it's +/-13V so you need to convert that to levels that the USB comms chip can handle. The units I linked to above do, but most don't - if in doubt, the board should have two chips on it. If it doesn't it might work, or it might fry something. If you're not 100% sure, double check your requirements: the RS232 label is often incorrectly used as a catch all for any serial protocol. Google "RS232 RS485 RS422" and wade into the sea of standards. The big clue is RS232 has a single signal line, most of the others have two. You can do it with a cape, I'm working with RS422 which is another variation of serial protocol so I'm using a stack of driver chips on a custom board and it works fine. I believe there are RS-232 capes you can buy, but given how easily you can get USB adapters like the one above, I'd use those with a powered hub and save yourself the hassle. Cheers... Mike On 30 December 2013 18:10, Bruce Bowler <[email protected]> wrote: > Hi, I'm a newb to the whole beagle/pi/arduino world, but from what I've > seen, beagle appears to have the best 'support system' so I'm going to > start here. I'm also not a 'hardware guy'. > > I've been asked to design what is basically a data collection system, that > will have between 4 and 6 instruments connected to it. All of them are > 'off the shelf' sensors that have, as their only means of interface, rs232/ > db9 connectors (yes, I could change the db9's to something else :-) > > In poking around it seems that the best way to get those inputs into the > system is with a 4 or 8 port USB hub. Is that a correct assumption on my > part or is there a way to get ports "directly" onto the system with some > sort of multi-port cape? If the answer is "you can do 4 but not 6", I > could probably live with that, as physical mounting space is somewhat > limited where all this has to go. > > Thanks! > Bruce > > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
