What is the equivalent of \usepackage[T1]{fontenc} in plain TeX?

Question

I have inherited a semi-small TeX project in which I, after syncing across various computers and OS'es, had some problems with encodings of special characters like åäö.

My initial approach for fixing this was to convert everything to UTF-8 (using the iconv utility on Ubuntu), which made all the weird incorrect replacement characters disappear. However, the special characters still don't show up.

If this was LaTeX, I'd do \usepackage[T1]{fontenc}, but that doesn't work here because I compile with pdftex.

What do I do instead?

Answer 1

At first you don't need an equivalent for fontenc but for inputenc. You should (like inputenc) make the non-ascii chars active and map them to suitable commands. E.g. in an 8-bit encoded file you could do something like this:

%OT1-encoded font
\catcode`\ä=13
\defä{\"a}

Räuber
\bye

When using a T1-encoded font life is a bit easier, as a lot of chars are already in "the correct position". So the catcode changes are often not really needed, but as you can see with the ß some chars can be wrong if you don't add a definition

%Use a T1-encoded font:
%\catcode`\ä=13
%\defä{\char"E4}
% \catcode`\ß=13
% \defß{\char"FF}
%
\font\test=ecrm1000 \test

Räuber öäüß
\bye

With an utf8 encoded file life gets much more complicated as then you will have to recreate the parsing of the utf8 octets.

Addition

With the csplain or pdfcsplain format (http://petr.olsak.net/csplain-e.html) you can use utf8 directly.

öäüß

\bye