http://nguipxnkrp3qrzrlduhsatpcpwehnblzmlkc5ifiumxq4z5jlh4lwvid.onion/os_archive/os_OPSEC_357.html
Stick to lawful non personal, business and fact relaying only conversations over the telephone, (ordering takeout, calling the government, job interviews, etc). If you can, get a tape deck answering machine. Most of the modern digital answering machines allow (key code) remote playback.