Re: Apple IIgs <--> PC question

[supertimer@aol.com (Supertimer)]

Jonas Bevren <jbevren@yahoo.com> wrote:

>Supertimer (supertimer@aol.com) wrote:
>
>> Jonas Bevren <jbevren@yahoo.com> wrote:
>> 
>> >I'm guessing in the dark here, but since the IIGS's ports are mostly super
>> >serial compatible, I"d say they act like 6551 ACIAs at the appropriate slot
>> >I/O pages (uhg, been a while, I cant remember the addresses)..  Am I right?
>> 
>> Nooooo!  In fact, programs that try to treat the IIGS' serial ports as
>> though they were Super Serial Card 6551 ACIAs (like ADT) fail
>> miserably.
>
><duck, cringe, running for cover> =)

Oh no.  I didn't mean that to sound like a flame.  Too bad it
is not possible to convey subtleties with words, but it was
more of a shocked response than a flame.  You see, I've
had people tell me my IIGS was nothing more than an 8-bit
Apple II too many times, so I guess it was just that side of
me reacting.  Sorry.  ;-)

>> For null modem purposes, the IIGS can do 57.6k which is quite
>> an improvement over a Super Serial Card.  If the other computer
>> is a Mac, you'd want to use AppleTalk through the ports which
>> will allow 230k speed.
>
>A couple comments =).
>
>If you remove the crystal from the super serial card, and replace it with
>one that's twice the frequency, all data rates you select will be doubled in
>reality.  i.e. to get 115k on your trusty super serial card, install a
>2x-speed crystal, and select 57.6k.  I dont know how well apples handle a
>flood of IRQs (or does the SSC use NMI?), but you dare not do that on a
>stock c64 (where the modification originated, in the 6551-based swiftlink
>cartridge).  A stock c-64 can hit 38400 without a sweat, a stock c-128
>(which is blessed with 2mhz speed) can hit 115k with a slim enough serial
>driver.  It's quite impressive in fact.  My rommate is connected to one of
>my linux boxes via a 25-foot nullmodem cable, and uses 115k constantly with
>his accelerated 128-in-a-tower.

This mod exists for the IIe too.  It is called the Turbo ASB
which is a clock-chipper for the Super Serial Card.  It is
actually a little card with a faster crystal.  The card lets
you select boost or no boost.  There is also a replacement
6551 because the ones on earlier Super Serial Cards had
a faulty instruction while hardware handshaking.

At those speeds, I've read that there are some dropped
characters on a stock IIe, but on a IIe with a ZipChip
(8Mhz) all is well.

>Last, =) I thought appletalk was 280kbit SDLC, or is it tolerant of speeds
>varying that far?  I hate to nit-pick, but people need to know the right
>numbers (even me IF I'm wrong!) =)

I'm not sure.  My 230k figure is an approximation because
I keep on forgetting the exact figure that Jeff Blakeney gives
me.  I'm sure if he is reading this, he'll provide the exact
figure.  Nit-picking is good, but I seem to rely too much on
others to fix my figures.  ;-)