Re: 57700 throughput on 19200 serial port?

[dockery@griffin.cuc.ab.ca (Sean Dockery)]

I did not see the original article; instead I am extracting it from a reply.

In <33k034$s11@ntuix.ntu.ac.sg> ghblee@ntuix.ntu.ac.sg (Lee Han Boon) writes:

| I assume the SCC is some Super Serial Card thing (or something similar).
| How about the modem port of the GS, which has a max baud rate setting of
| 19200?  How fast have you folks gone with modems connected to that?  (I know
| this may sound silly, but since Luigi mentioned something about ProTerm
| "forcing" his GS to go at 38400, I'm hoping that >19200 speeds may be
| possible.)

SCC is the short form of Serial Communications Chip; in the context of an
Apple IIgs, it is synonymous with "the modem port" or "the Z8530".

The SSC (Super Serial Card) does not have an SCC; instead, it has an ACIA,
or Asynchronous Communications Interface Adapter, also known as "the 6551".

Apple Computers decided to make the control panel conform to the firmware's
limitation of only being able to set bps rates of 19.2 kbps and lower.  The
firmware inherited this limitation in that it was designed to emulate the
SSC firmware; the "^AnnB" command for setting the bps rate will not accept
numbers greater than "15".

By the way:  "bps (bits per second) rate" is the correct terminology for
talking about modem and port speeds; "baud rate", although widely accepted
as correct, is not.  Although if you use correct terminology around
salespersons, you could end up getting a variable speed blender instead of
a V.FAST modem.  ;-)

Are you using ProTERM, or just Luigi?  Uh, not you using *Luigi*, but Luigi
using ProTERM, and not you.  Um, Luigi, not you, using ProTERM.  Whatever.

I have a copy of ProTERM 2.2 from which I have lost the original disks (I
bought it used).  All of the ProTERM modem drivers (back then) were limited
to speeds of 19.2 kbps and lower; as such, ProTERM would not allow the bps
rate to be set above the maximum speed at which the modem could handle
transput.  There was a patch going around that would allow you to fool
ProTERM into thinking that the modem was faster than it actually was, so
your DCE/DTE bps rates could be set higher.  I installed this patch and
have long since forgotten what it was.

Under ProTERM 3.1, I doubt that Greg would have kept this limitation (it
annoyed a lot of people).  But, as I am not a ProTERM 3.1 owner, I can't
confirm this.

PS:  Does ANYONE out there have a Z8530 reference card or programming
reference?  PLEASE contact me at the below address.
-- 
Sean Dockery             |"Now my charms are all o'erthrown, and what strength
dockery@griffin.cuc.ab.ca| I have's mine own." -Prospero, "The Temptest"