I was at work with a co-worker that said back in the 70's, he believed, that it was illegal for any FBI, Police, Etc..., to listen to any phone conversation for longer than 90 seconds.

Is he correct and, if he is, does this still apply today?

Also, how in the heck is this supposed to be the law when they were planting 24-7 recording devices in certain places?

I believe that up until this present day, you must have a court order to even be allowed to listen into anyone's private conversations.

Any info on this topic is appreciated.