Custom Letters and Punctuation Not Working

For some reason when I try to add a forward slash or any other letters or punctuation, I get a box instead. Numbers are working fine and the fnt file has a forward slash graphic for it. Not sure what part of my code to include to help fix the problem but this is the function I'm working on. 

function drawDate(dc) {
   var nowinfo = Greg.info(Time.now(), Time.FORMAT_SHORT);
   var homeDay = nowinfo.day;
   var homeMonth = nowinfo.month;

   dc.setColor(Graphics.COLOR_ORANGE, Graphics.COLOR_TRANSPARENT);
   dc.drawText(dc.getWidth()/2 + 10, 30, digitalSmall, Lang.format("$1$",[homeDay.format("%02d")]), Graphics.TEXT_JUSTIFY_LEFT);
   dc.drawText(dc.getWidth()/2 - 10, 30, digitalSmall, Lang.format("$1$",[homeMonth.format("%02d")]), Graphics.TEXT_JUSTIFY_RIGHT);

   //This is where I'm getting a box
   dc.drawText(dc.getWidth()/2, 30, digitalSmall, "/", Graphics.TEXT_JUSTIFY_CENTER);

//This is for my font in fonts.xml

<fonts>
<font id="digitalSmall" filename="digitalSmall.fnt" filter="0123456789"/>
<font id="digitalLarge" filename="digitalLarge.fnt" filter="0123456789"/>
</fonts>

Thanks!