Uvital Phone Jack to Ethernet Adapter, RJ11 to RJ45 Adapter, RJ45 Female to RJ11 Male for Landline Telephone, with RJ45 to RJ11 Cable (Black,2 Pack): Amazon.co.uk: Electronics & Photo
How to Connect a Phone or Tablet to the Internet Using an Ethernet Cable | PCMag
Telephone jack to Ethernet? : r/HomeNetworking
networking - Convert RJ11 to ethernet cable? - Super User
RJ11 - RJ45 Cable (5 Metres)
How to Connect your Receiver and Modem with an Ethernet Cable