8P4C- 6P4C. RJ11 to RJ45 Cable. The flat four core cable is wired straight through.
deleyCON 0.5m (1.64 ft.) Telephone Cable RJ11 to RJ45 Modular Cable Flat Cable RJ11 Connector to RJ45 Network Connector Telephone Socket Modem Router Fax ISDN DSL VDSL Internet Black : : Electronics
RJ11 6P4C TO RJ45 8P8C EXTENSION CABLE FOR ETHERNET MODEM ADSL DATA PHONE PATCH BROADBAND HIGH SPEED BT INTERNET CONNECTION - AliExpress
RJ11 to RJ45 Ethernet Telephone Cable 8P4C 6P4C ASDL Patch Lead White
RJ11 TO RJ45 Modem Cable Connect Router To ADSL RJ45 Socket Patch Lead HUB Lot £3.75 - PicClick UK
RJ11 6P4C to RJ45 8P4C Modular Phone Internet Extension Cable 3 Meter
deleyCON 0.5m (1.64 ft.) Telephone Cable RJ11 to RJ45 Modular Cable Flat Cable RJ11 Connector to RJ45 Network Connector Telephone Socket Modem Router Fax ISDN DSL VDSL Internet Black : : Electronics
DSL/Phone Cables (RJ-11), Networking Cables & Adapters, Computer Cables & Connectors
5m RJ11 to RJ45 Cable Ethernet Modem Data Telephone ASDL Patch Lead Broadband High Speed BT Internet Plug 6P4C to 8P8C Flat Network Extension Cord Compatible with Modem, Router, Landline Wire (Black)
RJ11 6P4C TO RJ45 8P8C EXTENSION CABLE FOR ETHERNET MODEM ADSL DATA PHONE PATCH BROADBAND HIGH SPEED BT INTERNET CONNECTION - AliExpress
Telephone Extension Cable 20 m BT Telephone Extension Cable Complete 6-Wire Male to Socket for Office & Home Broadband Cord Compatible with Phone, Fax, Handset, Modem (White) : : Electronics & Photo
Telephone Cable RJ11 4-Wire (20m) - Cablematic
RJ11 6P4C to RJ45 8P4C Modular Phone Internet Extension Cable 3 Meter