LC-28 · Privacy
Recording a call without telling the other person
One party knows
In ordinary words
In most states, a person who is on a phone call can record it without telling the other person. In a minority of states, that secret recording is a crime.
Why people call it a crime
Secretly taping someone feels like a violation either way. The map of the law is a patchwork, and people get it wrong at the state line.
A scene, not a hypothetical statute
A worker in Texas records a boss admitting a wage shortfall. Texas allows it. The same recording made in California, without telling the boss, can be a crime. The confession feels identical. The statute does not.
In legal terms
Federal wiretap law, 18 U.S.C. § 2511, is one-party consent: a person who is a party to the communication may record it. Twelve states generally require all-party consent, including California, Florida, Pennsylvania, and Illinois, with exceptions. Recording a call across a state line can implicate the stricter state. Recording a conversation you are not part of is eavesdropping and is usually a crime.
Congress chose one-party consent so people could record their own conversations, including for evidence. States may be stricter.
18 U.S.C. § 2511; state all-party consent statutes (e.g. Cal. Penal Code § 632).
Where it stops being legal
Recording in an all-party state without consent, recording a call you are not on, or recording in a place with a reasonable expectation of privacy you do not share can be criminal.