[Coco] Question about telnet control codes for the Coco3

Aaron Wolfe aawolfe at gmail.com
Tue Jul 15 10:15:18 EDT 2014

There are several issues.  In OS9 you have the ability to set some of the
values used to indicate certain controls in the device descriptor.  PD.int
and PD.quit come to mind.  I don't recall if there is a PD.clear
equivalent, but even if there were it would probably need additional help
on the coco side since you are really asking to change devices from one /w
to another which is going to require cooperation by the window driver.

You can find a minimal implementation of the telnet protocol in the telnet
client for DW, found in the nitros9 cmds and netlib source.  This mostly
just strips out things that would confuse the SCF driver and tries to
convince each side to talk to each other, nothing fancy.

Without some help in the form of an SCF module that understands more than
the stock /t2 does, I think results will be that some programs just can't
work.  I managed to get full screen text mode programs and even some
graphical os9 applications working over DriveWire by (re)implementing most
of the  windowing on the client side, this had decent results but of course
is quite different since it requires a special client and doesn't work at
all with standard terminal programs.  I could split that out from DriveWire
and probably make it work as well via direct serial connection, it would be
much too slow to do graphic programs but probably OK for text.  It still
isn't quite right but much better results than I ever managed trying to
translate standard terminal things into OS9.  If that is of interest I'll
give it a shot.
On Jul 15, 2014 8:55 AM, "Robert Gault" <robert.gault at att.net> wrote:

> I've been working with Kandur to get a PC telnet program to connect with
> the Coco3 via a /t1 serial connection. Kandur has found that SecureCRT
> works very well at 9600baud with no glitching. The big problem with this
> type of connection is that all I/O is done through the PC keyboard not the
> Coco keyboard. So, how does one map the special Coco key CLEAR to a PC
> telnet terminal.
> The Coco makes use of the keyboard matrix to recognize the special keys.
> The obtained values have little if any relationship with the ascii control
> codes. That suggests that it would be impossible to send a character or set
> of characters by telnet to the Coco3 to permit changing windows under OS-9.
> There are other problems with some OS-9 programs which don't like telnet
> connections. One example is Vaughn Cato's VU which can't handle a telnet
> space character.
> Has anyone solved these problems and if so how did you do it?
> Robert
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