Unix accommodating 3278 Terminals

[Phil Howard KA9WGN]

rickert at mp.cs.niu.edu (Neil Rickert) writes:

> This probably can't be done.  The vt100 terminal is unbuffered.  Each
>keystroke is transmitted immediately.  The 3278 is buffered.  Up to a complete
>screenful of data is buffered on the terminal/control unit.  The host doesn't
>even see a keystroke until the ENTER key or one of the PF keys or PA keys is
>used.  At that time the complete screenful may be transmitted in a block
>operation.

> You can use software emulation, as in 'tn3270', to emulate a buffered terminal
>with an unbuffered one.  All the emulation software must do is provide the
>buffering and screen management.  Going the other way is a little more
>difficult, unless you have extra sensory perception built into your CPU.

Neil is right on the mark, except that I'd have used "definitely" in place
of "probably".

There are terminals on the market that can simultaneously behave like an
IBM 3278 over a 93 ohm coax port and like a VT??? over an RS-232 port.
There might well be derivatives of these that work on networks and do
TN3270 emulations.  PC and MAC programs also exist (NCSA/Clarkson TELNET).

But if you are trying to retrofit existing hardware base of IBM 3270 class
terminals, your time is better spent getting funding for new hardware.
-- 

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< Phil Howard -- KA9WGN -- phil at ux1.cso.uiuc.edu                              >
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