Re: Adt(pro)

[BLuRry <brendan.robert@gmail.com>]

> > > The $10 stored in the control reg selects 1 stop, 8 bits, ext rx clk,
> > > XTL/16 bps where XTL = 1.8432 MHz so the baud rate is 115200 bps.
> > > The $0B is stored in the command reg and selects no parity, no echo,
> > > RTS & DTR asserted, no IRQs.
>
> > So, uh, can you set an external modem this way?

If you want the 56K modems to use their built-in data compression, you
have to set the port at a faster speed than the modem.  That much I
remember from a decade ago.  I used to set my PC's port to 115.2 to
get the max out of my modem (didn't make it connect higher than 56k,
but it did enable better inline compression of text)

> 3) You really need an accelerator card/chip to take advantage of the
> higher throughput.

Sort of.  If you want to use the rom firmware, then most likely it
might be too slow.  If you poll the port directly, you can send/
receive with no big issue.  I was able to confirm this with a non-
accelerated //e (super serial card) and a rom 0 //c.  I did error on
the side of paranoid though, since it's an undocumented/unsupported
setting, and implemented a really simple checksum to prevent
transmission error.  I haven't tried this setting with any apple
communications software, just bare-metal programming.

Of course, if you're using Y-Modem Batch or Z-Modem, then you're
already using a transmission protocol with error correction.

-B