Help connecting router to socket

[WF23]

I have moved house. My previous house had a double connection phone socket (so the smaller head as shown fitted in the slot on phone socket ok) My new house only has the larger connection socket. So I'm wondering, do I need a cable where the small end plugs into purple part of router, and the other end has the larger connector, or do I need some sort of adapter, so the smaller end fits in and then I can connect to phone socket. I hope this makes sense. TIA

[TimmyBGood]

@WF23 

You'd need either an RJ11 to BT jack cable, or a plug-in microfilter.

 

[WF23]

Thank you so much for reply and help