Actually, in many cases a USB port is used in conjunction with a USB<->Serial converter chip, like the FTDI series, precisely to allow a product to be accessed over USB without changing the serial protocol originally used over the RS232 interface. The USB interface is exposed to software on the PC via a virtual COM port, by means of the driver supplied by the USB<->Serial port converter chip vendor. Existing programs continue to work just fine.
I've done this for years at work, adding a USB port to our products using an FTDI converter chip which is demanded by those customers using laptops without an RS232 interface (and who do not want to mess around with outboard USB<->Serial converter cables). In many cases the product retains the original RS232 interface with DB9 connector as well, so the device can be accessed one way or the other. The serial control protocol is unchanged. Even firmware updates are done over the USB interface, just as they were done over the RS232 interface. It's no big deal to do this if all you need to do is sustain an existing serial control protocol and PC software, rather than implement digital audio transport over the USB interface. Bob NW8L On Sat, 10 Nov 2012 01:31:11 -0800 "Fred Townsend" <ftowns...@sbcglobal.net> wrote: > MORE IMPORTANTLY, if you replace RS232 with either an interface or > USB, you break the code of every ham radio program out there that > uses an RS232 interface. That is not a trivial matter. It's still a > shovel with a rope handle. > 73 > Fred, AE6QL > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
