Since Perl 5.8, Perl uses an IO stack called PerlIO. Layers can be added to the file handle to perform tasks such as LF<=>CRLF conversion and character encoding.

It's possible to override the defaults when you create a file handle. It's also possible to modify the layers later on using binmode.

It appears that connect does not add the default layers, so it effectively calls binmode. There's no harm in calling binmode yourself to be safe. binmode with no third argument removes/disables any :crlf and :encoding layers.