[TRLog] Re: Polling

[Larry Tyree]

Rod, N4SI, writes:

> Because of this polling, 4800 is the max rate that TRLog can use for 
> packet interface. This is the way I understood Larry's explanation; 
> he can correct me if I have it wrong.

Actually - this paragraph is correct.  However the polling has nothing
to do with detecting baud rates from the TNC.  It instead explains the
method TR uses for checking the serial ports.  

One method (not used by TR) is to use interrupts.  TR doesn't use
this method mostly because it just never has.  The advantage is 
you don't have to worry about your IRQ settings.  The disadvantage
is that if you send characters to a serial port faster than the 
program is checking the port, you will lose characters.

TR checks the ports once every 1.68 milliseconds - which means it
can safely support baud rates up to 4800.  

I am not aware of any real performance impacts of running at 4800
baud instead of 9600 baud.  Probably the port that is affected by
this the most is the multi network - but I believe there is plenty
of bandwidth there for any real configuration.

Tree N6TR
tree@contesting.com

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