At 12:31 PM 7/8/2007, Tim Ellison wrote: >Neil, your prediction will, unfortunately probably come true. > >Your concern was debated before the FlexWire physical connector was >selected. In the end, the decision was made to use a 9-pin d-sub >connector (that is used for serial connections, but not exclusively), >but orient the connector upside down from a standard serial >implementation
UPSIDE DOWN? Surely you jest? There is NO standard orientation. For most "tower configuration" desktop cases the long axis of the connector is vertical. And, when reaching around behind a bunch of equipment, that's a pretty lame way to prevent mismating. >and provide a warning label to prevent incorrect usage. >So the back panel is CLEARLY labeled not to connect a serial cable to >the FlexWire port. Hopefully this will be a sufficient deterrent. Actually, it DOESN'T say not connect a serial cable. It says "Caution Flexwire Only".. More to the point, what happens if someone does hooks up a standard RS232 cable to it? The standard says that the port can source 20-30 mA at 12-15V (either polarity). Since Flex isn't publishing schematics (of at least the interface "end circuit") I would think that it's incumbent on Flex to fully specify the behavior. Otherwise, it's like using a 110V power plug to carry FlexWire data, and saying, well, we told you not to plug it into the wall, it's not our problem you're a stupid idiot. (Which, as you can imagine, is awfully condescending to your potential customers.) If someone DOES hook up a an RS232 cable, and it cooks something, is repair covered under the warranty? >Also, blocking the holes in the d-sub connector would work, but if you >wanted to build a FlexWire device, then you have to find a special d-sub >male plug that has the correct pins missing. That would be an impediment >for people wanting to innovate by building FlexWire devices. Hardly. A pair of cutters zaps the pin right out of there, if you use a prebuilt cable/connector assembly. If you're using a bare connector, you just pull the pin out. No hunting and searching for a custom connector. If you had said, we're using this exotic Lemo connector made only in Switzerland, or one of those oddball tiny connectors favored in cellphones and compact equipment, I'd believe the rationale of "not having an unusual connector. This all sounds like "after the fact" rationalization. I don't have a problem with a DB9. It's a standard connector, you can use standard cables, etc. I'm assuming you didn't make it hideously sensitive to applying incorrect voltages.. there ARE clamps and current limiting resistors, right? And, that you tolerate pin 1 being grounded. Or is it just connected up to the pins of an expensive non-socketed part that's ESD sensitive too, so zapping it kills your radio? Tell us it isn't so. Jim, W6RMK _______________________________________________ FlexRadio mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ FlexRadio Homepage: http://www.flex-radio.com/
