Decided to finally get rid of this eyesore in the entrance of our home. (don't mean the bad paint job by the way)

When I removed it there was a nice gaping hole and behind it with this.

I'm assuming it's telecom related but a bit stumped as to why it would be in the wall of our house. The house I think was built in the 60s. If anyone can shine some light on this I would be grateful. I Plan to gib over it but be nice to know what it is and why it would be there.

Thanks