If I am talking to person A and person A purposely calls person B and puts the phone on speaker so person B can hear the conversation without my knowledge or permission is person A in violation of wire tapping/interception law?
This is an area governed by state law. In the case of interstate calls, the more restrictive state law applies, so it would be important to know if all parties were in the same state or, if not, what state(s) they were in.
Most state laws are pretty specific about unknown recording of a call being a crime, not so much about allowing a 3rd party to listen in unbeknownst to one or more of the other parties.
Your specific case seems to me to be the ethical equivalent of motioning someone in from another room and allowing them to hear the telephone conversation. I’m not sure it’s illegal, but it seems highly unethical.
FYI, per this site the Maryland wiretap law specifically mentions recording: