From Bob Day:
Phone Recorder for Windows 10 is a software application for landline phones that allows you to join and record an ongoing telephone conversation. It runs under either 64-bit or 32-bit Windows 10. Phone Recorder doesn't have much of a user interface -- just two buttons: "Start recording/Stop recording" and "Exit". When you click on "Start recording", Phone Recorder will join an ongoing phone conversation on the same line as that of the modem, and the button label will change to "Stop recording". The conversation is stored as a .wav file in the same folder as the Phone Recorder executable (.exe) file. To run Phone Recorder, you need to have a USB phone modem that has voice capability and a Conexant chipset, such as a TRENDnet TFM-561U. Phone Recorder uses only the voice feature of the modem -- there's no need to "dial-up" anywhere. Be sure to tell the other party or parties on the line that you are recording the conversation if it is legally required to do so.