General Information on Terminal Emulation
The instructions that you give a computer can only work if
they are written in a "language" that both your communications
program and our computers can understand. Because your
communications program is making your computer act like a
terminal that is under the control of our host machine, that
language is called your terminal type, or
terminal emulation.
Some terminals were smarter than others, with screens that
could do all sorts of things, and could change the language
they were speaking at the flick of a switch (or in response
to an order from the remote machine). The smartest terminal
of all in those days was DEC's VT100, whose
language came to be something of a standard.
Say your communications program tells a host computer to
speak "vt100". Then, the host will send you
vt100 control sequences. If your communication
program does speaks vt100, things will
happen properly on your screen. If your program
doesn't, you won't know what are regular text
characters and what are control sequences, so you will end up
seeing them all on the screen, as if they
were text, resulting in pure and utter garbage.
The worst case is when your program is set to not understand
any language. The oldest terminals were
Teletype paper terminals, which by
definition could only scroll text. A terminal-type that can
do nothing but scroll text is named after them:
TTY.
At the other extreme, if the host computer thinks that the
language you claim to speak is too weak to do the things you
want to do, it will refuse to let you do those things.
What to do about these problems
The first problem is something that only you can cure, by
turning on your communications program's terminal emulation
for ANSI or vt100 (or any
vt-number higher than that). Usually you will find this in a
sub-menu called something like Terminal,
under a Settings or
Configure menu. You might find it in the index of
your manual under Terminal or
Emulation.
The second problem -- say, not being allowed into pine or
lynx because your terminal type is too weak, even when you
tell our host computer that you are a vt100
-- is easy to solve.
Overkill -- If your communications program
says it is a vt102 or vt220
or vt340, think twice before you tell our
computer you're anything more than a vt100.
Most of the functions you'll need for text-only work on an
account are contained in that "limited" terminal type. Our
machine may never have heard of some of those other
terminal-types, and will thus consider you a
TTY.
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