info-mac@uw-beaver (info-mac) (08/10/84)
From: Thomas.Newton@cmu-cs-spice.arpa
The other day, I was using MacTerminal & macget to upload some MacPaint files
to the Vax and had problems uploading several of the files. Somewhere in the
middle of each transfer, the phone line would go dead, and soon afterwards the
Mac would put up a dialog box reporting an I/O error.
I am using one of the Alpha versions of MacTerminal and have a U.S. Robotics
Autodial modem, which is basically similar to the Apple 1200 (read Password)
modem. The Vax was very lightly loaded (it usually is at 4 A.M.).
When I substituted my 300-baud acoustic modem for the Autodial, I was able to
upload all of the files without problem (albeit VERY slowly).
I suspect the problem is that MacTerminal sent three "+" characters in the
middle of the transfer, thus causing the modem to hang up. Since the 300-
baud modem doesn't recognize any special characters, it worked just fine.
However, given that the Apple, Hayes, and U.S. Robotics modems all treat the
"+++" sequence as a command to the modem, MacTerminal really should take care
not to send a "+++" sequence when it can be avoided.
When sending files to another computer, it is probably not possible to treat
"+++" as a special case. When sending files to another Macintosh (or a Vax
pretending to be a Macintosh. . .), MacTerminal should encode "+++" to avoid
possible interference from the modem.
-- tdninfo-mac@uw-beaver (info-mac) (08/11/84)
From: Joseph I. Pallas <PALLAS@SU-SCORE.ARPA>
I've never actually tested it on the USR Password I use, but on a REAL
Hayes modem, the +++ sequence must be preceded and followed by a full
second (default, is adjustable, I think) of no data to prevent just
this sort of confusion. If the USR/Apple doesn't do this, then Apple
has screwed up. Probably the people writing MacTerminal use a real
Hayes, since it's so much better (personal opinion, of course); that
might explain why MacTerminal doesn't do some of the things that it
wouldn't have to do if you were using a Hayes instead of a USR/Apple.
joe
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Date: Thursday, 9 August 1984 17:46:12 EDT
From: Thomas.Newton@cmu-cs-spice.arpa
To: Joseph I.Pallas <PALLAS@su-score.arpa>
cc: info-mac@sumex-aim.arpa
Subject: Re: Apparent MacTerminal BUG
Message-ID: <1984.8.9.21.41.53.Thomas.Newton@cmu-cs-spice.arpa>
According to the manual for my USR Autodial, it also requires a full second
of silence before and after the sequence. Although the length is fixed, you
can change the "+++" to any other sequence of three identical characters.
-- tdn