Found strange old device wired in at rental home, possible microphone ?

So I found this box pretty low on the wall of the bedroom near the base of the bed. It looked old to , as it has an old port and the house is quite old as well. Being curious, I decided to unscrew the top and check it out. Not really sure what I'm looking at now. Were these sorts of ports normal to have around during dial up? And, most importantly, is this black thing that was at the end of the black wire coming out the case a microphone?

Thx u