Re: CM11 Status Request (C# Language)

[nobody@xxxxxxxxxxxx (Dave Houston)]

Neil Cherry <njc@xxxxxxxxxxx> wrote:

>On Thu, 23 Nov 2006 06:00:25 GMT, Charles Sullivan wrote:
>> I've seen some unusual behavior of USB->Serial adapters compared with
>> actual serial ports under Linux.  I've assumed these are bugs in the
>> Linux drivers but Windows drivers (for some adapters at least) may exhibit
>> similar behavior.
>>
>> E.g., a blocking read of N bytes may return after the first byte read.  So
>> Dave's polling ought to work, while expecting to get all N bytes with one
>> read may fail.
>
>I heard of such things and my understanding is that these USB/serial
>dongles are usually dongles meant for PDA's for some reason they have
>a lot of trouble acting as normal serial ports. I'm unsure as to why
>this is.

A lot of the cheaper ones don't do anything with the handshake lines. But
the CM11A doesn't use any handshake lines so even the cheap ones should work
as far as the hardware goes. As for driver flaws, that's a possibility,
although the complaints I've seen from Windows users can almost always be
traced to the missing handshake lines. They are slower than standard serial
ports because they must translate from/from serial-USB at each end of the
link but this isn't a major factor at 4800bps.

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