My parents have a Telecom POTS land line, and need the ability to record the two way audio of conversations on demand. We have a family member who is making a number of phone calls of an abusive nature that currently don't quite meet the threshold to be threatening enough for police intervention, but may be required by future legal proceedings.

Can anyone suggest the best way to achieve this. Ideally, I would move them to VoIP where the calls could be recorded, however they are a little bit nervous about the reliability, and I am in another country so can't help them get all the gear and get it setup etc.

Are there any phone handsets out there that have the ability to record calls? Any other suggestions that don't involve a move to VoIP?