Serial comm differences between PC & Mac?

[Gordon Tillman]

Howdy!

About this:

> I am connected via a serial cable (on OSX with a Keyspan serial 
> adapter)
> to our phone system to capture our call data. Thanks to Sarah's serial
> stack (THANKS, SARAH!), I got up & running quickly & everything works
> great. But when I unplug from my mac & plug into com1 on the PC & use 
> my
> program, I'm getting different results.

I'm working on a form scanner application in RR that runs on Mac OS X 
and Windows.  I, too, use a KeySpan serial adapter to hook the form 
scanner to the Mac.  I found something very interesting.

As you know, you put your settings into the serialControlString before 
you open the connection.  I found that if I used a parity setting that 
was correct according to the device I was hooked to then I would get 
extra characters in the data that was read from the external device.

But I found that if I changed the PARITY value in the 
serialControlString to us no parity; e.g., PARITY=N, then the data was 
read correctly, with no extraneous characters, even though the device 
was using odd parity.

I am thinking that the KeySpan driver was massaging the data somehow, 
or else automatically doing the parity negotiation with the external 
device.

NOTE:  When I used the same device with the same KeySpan adapter, 
plugged into the USB port on my Windows machine, I did not see this 
phenomenon.

I don't know if this is what is causing your problem or not, but it may 
be worth looking in to.

--gordon