Re: upgrades for //c

[sbdocker@acs.ucalgary.ca (Sean Brendan Dockery)]

In article <1993Jun8.095258.13574@actrix.gen.nz>
dempson@swell.actrix.gen.nz (David Empson) writes: 
|In article <93Jun04.081422.30045@acs.ucalgary.ca>
|sbdocker@acs.ucalgary.ca (Sean Brendan Dockery) writes: 
|> 
|> The 1200 bps limitation that is continually being mentioned is with
|> regards to the built in port 2 firmware; it will only let you toggle
|> between 300 and 1200 bps.  (This is that dumb terminal you can get to
|> by typing "IN#2" following by "^AT" from the "]" prompt.)
|
|Nope, wrong.
|
|The original IIc (unmodified motherboard) has a problem handling 1200
|baud or higher because the 6551 ACIAs are not being clocked at the
|right frequency.

[ snip ]

I'll try to put this more clearly.  THE FIRMWARE limits the bps rate
that you can toggle in DUMB TERMINAL mode to 1200 bps.  That was the
only point that I was trying to get across.

I am not a techie and would not dare to claim that I am aware of the
all the problems with the 6551 chips on the original IIc motherboard,
let alone describe them.

I use my original IIc with a 2400 bps GVC MNP-5 modem after setting
the port speed to 9600 bps using my terminal program.  I have not
experienced any character scrambling of any sort, even when the the
bps peaks at ~4800--subject to your error prediction, of course. =-)

|David Empson
|dempson@swell.actrix.gen.nz

Does this topic belong in another group now?  Hmmm...
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