[ILUG] Getting the most out of serial ports..

[Colm Buckley]

> I've a 3COM ISDN Pro TA, and I'm wondering how to run it as fast as I
> can on my serial ports which are 16550A's.. I assumed that I could use
> Setserial to set this up, which I thought I had done, but I don't seem
> to be able to get anywhere near that.... I'll be experimenting more
> tomorrow.  Anyone who's already looked at this I'd appreciate their
> input.

The 16550A's themselves can in theory do up to 460kb/s, but the
supporting hardware may not be able to cope.  I've happily run 3Com TAs
off a 16550A at 230400bps using the following:

       setserial /dev/ttyS0 baud_base 230400
       stty 230400 < /dev/ttyS0

On my Debian system, the serial settings are applied at bootup, and are
read from the file "/etc/serial.conf" - in there, there's a line:

/dev/ttyS0 uart 16550A port 0x03f8 irq 4 baud_base 230400 spd_normal

which has the desired effect.

It shouldn't harm anything to at least try this, and if it doesn't work
you can always fall back to 115k2, which is only a little bit short of
dual-channel ISDN's theoretical max. throughput.

           Colm


 -- 
Colm Buckley BA BF | NewWorld Commerce, 44 Westland Row, Dublin 2, Ireland
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