RJ11 – Regitered Jack 11 – is used for the landline. It is an international standard for connecting the fixed telephone to the telecommunications network.
RJ11 uses a 6-slot connector. In this one RJ11 has 6 slots (positions) and two drivers, the standard is written 6P2C.
The information transmitted on the line can be digital (DSL) or analog.
The telephone cable that arrives at the subscriber has 4 conductors grouped into 2 colored pairs called twisted pairs. Only the two central conductors are used for the line.