Amazon.com: Xsusmdom [2-Pack] Phone Jack to Ethernet Adapter, Ethernet to Phone Line Adapter RJ45 Female to RJ11 Male Converter Adapter Cable for Landline Telephone Service : Electronics
1-Wire Bus 1x1 Coupler, 6P4C (RJ11) Connectors - Sealevel
6P4C RJ11 Female to Dual Female Socket + 8P8C RJ45 Female to Female F/F Adapter Networking Cables - Walmart.com
Tripp Lite RJ11 Modular Straight Through Inline Coupler Telephone F/F - phone coupler - P420-001 - Cable Connectors - CDW.com
NVT Phybridge RJ11 to Two-Screw Terminal Adapter NV-RJ11A-2P B&H
UIS Lighting Adapter Type-A, for RJ11/12 Connector Lights with PWM or 0-10V Dimmers - AC Infinity