Amazon.com: 1m RJ11 to RJ45 Cable Phone Telephone Cord RJ11 6P4C to RJ45 8P8C Connector Plug Cable for Landline Telephone (Black) : Electronics
Amazon.com: Keple RJ11 Cable ADSL 10ft Extension Lead Phone Cord Telephone Plug High Speed Xfinity Internet Broadband Male to Male Router and Modem to RJ11 Phone Socket/Microfilter/Landline Wire (Black) : Electronics
Newhouse Hardware 15 ft. Telephone Extension Cord, with RJ11 (6P4C) Connectors, Works w/Telephones, Fax Machines, Modems, Black (5-Pack) MLC15-BK-05 - The Home Depot
RJ11 to BT Landline Telephone Phone Cable Lead Modem FAX Plug BT Socket 2m - 10m | eBay