Connector punctuation (the default is probably not the right one for unicode):
<..latex ltoutenc..>
\NewConfigure{textundescore}[1]{\expandafter
\def\csname ?\string\textunderscore\endcsname{\leavevmode#1}}
\Configure{textundescore}{\HChar{95}}
-_-_-
The math underscore below is represented by a ruler drawing.
<..latex ltoutenc..>+
\expandafter\let\expandafter\OMS:textcircled\csname
OMS\string\textcircled\endcsname
\expandafter\def\csname OMS\string\textcircled\endcsname#1{%
\def\:next{\OMS:textcircled{#1}}%
\def\:temp{#1}\expandafter\scan:textcircled\a:textcircled{}<.par del.>%
\:next }
\def\scan:textcircled#1{\def\:tempa{#1}\ifx \:tempa\empty
\expandafter\gob:textcircled
\else
\ifx \:tempa\:temp
\expandafter\expandafter\expandafter\found:textcircled
\else\expandafter\expandafter\expandafter\cont:textcircled \fi
\fi}
\def\found:textcircled#1#2<.par del.>{\def\:next{#1}}
\def\gob:textcircled#1<.par del.>{}
\def\cont:textcircled#1{\scan:textcircled}
\NewConfigure{textcircled}[1]{%
\def\:temp{#1}\ifx \:temp\empty \let\a:textcircled\empty \fi
\get:textcircled{#1}}
\def\get:textcircled#1{\def\:temp{#1}\ifx \:temp\empty
\else
\append:def\a:textcircled{{#1}}\expandafter\more:textcircled
\fi }
\def\more:textcircled#1{%
\append:def\a:textcircled{{#1}}\get:textcircled}
\Configure{textcircled}{}
-_-_-