uart vs sio differences ?

Marcel Moolenaar xcllnt at
Mon Dec 8 18:49:52 UTC 2008

On Dec 8, 2008, at 8:21 AM, Mike Tancsa wrote:

> Unfortunately, we only control the FreeBSD side of things and the  
> other end of the serial connection is a windows app we dont  
> control.  Everything seems to work ok from our side, but the other  
> side which we dont control seems to be missing some things we are  
> sending it and vice versa.

It looks to me that flow-control is disabled, is that right?

Not only does uart(4) make use of the larger buffer of the
hardware, it's also more efficient under puc(4) than sio(4)
is because of the use of the serdev I/F. It's possible that
the receiver can not keep up when uart(4) is used. A serial
line analyzer should tell you more...


Marcel Moolenaar
xcllnt at

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