Rj11 6p4c 2 Way Outlet Telephone Jack Line Splitter Adapter Beige - Telephone Cords - AliExpress
Amazon.com: CablesOnline, 1ft 3.5mm Jack to RJ9/RJ10 iPhone Headset to Cisco Office Phone Adapter Cable, IP-CS01 : Electronics
Converter Adapter | Converts RJ-9 to 2.5mm for phones that have a 2.5mm jack., (2200-11095-002) | Use with APP-50, APP-51 EHS for Polycom, Connecting telephone devices to 2.5mm headset mini jack
Uvital RJ11 Duplex Wall Jack Adapter Dual Phone Line Splitter Wall Jack Plug 1 to 2 Modular Converter Adapter for Office Home ADSL DSL Fax Model Cordless Phone System, White(2 Packs) - Walmart.com
3.5 mm TRRS to Slim 3.5 mm TRRS - Headphone Adapter | Hosa Cables
Lightning to 3.5 mm Headphone Jack Adapter - Apple
RJ45 to RJ11 Cable, 6 Feet Phone Jack to Ethernet Adapter RJ11 6P4C Male to RJ45 313107765728 | eBay
Telephone Adapter with Dual RJ11 plugs to 3.5mm Mini Phone jack for Recorder Pen | eBay