The RJ-11 cable is used to connect your Modem to your ADSL Broadband Telephone Line Microfilter.
The end connectors are Gold plated for improved data transmission and higher signal strength. 

*A short cable works best for this application allowing for less signal interference between other cables (especially power cables) ensuring a faster connection speed.
 
Specification

Length: 0.5 metres (1.5ft)
Configuration: Cross wired for ADSL (see diagram)
Type: 4 Core
Colour: White