Amazon.com: Telephone Line Adapter for Split the Line to Telephone and Voice Recorder, with Two RJ11 Port for Incoming and Outgoing Phone Connection and 3.5mm Audio Socket to Connect to Voice Recording
Telephone Adapter - Recording Calls, Agent Training, Plug into Handset Port
Sound Professionals SP-TELEPHONE-TAP - Adapter to record both sides of a conversation using a landline telephone SP-TELEPHONE-TAP
Amazon.com: VEC TRX-20 Telephone Call Recording Adapter with 3 ft. Cord and 3.5mm Plug. : Electronics
Recording Adapter with Telephone Line for Digital Voice Recorder Telephone Adapter Line-in Adapter for Dictaphone Recorder Pen - AliExpress Consumer Electronics