Didn't even think of that, yes of course XLR and for that matter, 1/4" TS/TRS connectors were originally for switching phones at AT&T, before automated switching. Incidentally, you can also blow up quite a bit of stuff with them, depending on whether they are at consumer "line level", pro audio "line level", or even speaker level. We're definitely too comfortable with "if it fits, it works" (or at least isn't harmful".