Using Fritzbox with BT infinity

Question

Hey Everyone,
I hope to be getting BT infinity installed soon and I know when you do a BT engineer and they put in a Modem AND a home hub router and they put the modem at the master socket and if you wish to move the router to a better location you pretty much just extend with an ethernet cable I assume.
The thing is, I have a Fritzbox 7390 so once the engineer is out the door I want to drop the BT kit and use my modem/router all in one that is infinity compatible but the router is set up up stairs where all my connections are and connects to the master socket via a telephone extension cable. 
My question is, is a normal telephone cable suitable for connecting the router to the master socket or do infinity houses have a special master socket with a special cable to connect them.
If so what cable would I need to connect my modem for the master socket, say about 30 m.
Also, am I likely to see any speed drop by moving the modem away from the master socket. Currently I get none as Ive tested it so I'd assume its the same but you never know!

Answer 1

I had FTTC installed last week. I am with an independent ISP. The engineer fitted an extension cable and carried out a line test plugging his test set directly into the socket. He took one look at my router (a Fritz!Box 7390) and called for advice. He returned with his laptop to show me that my order did not include an engineer set up and he left. I saw no point in plugging in the modem as setting up the FB for VDSL was just 3 clicks on the Account page. My connection has remained stable since install with no significant errors or speed drops. In fairness to the OR engineer, he did say that I was his first ever FTTC install. If you need a data extension cable and want to use the FB-provided splitter lead then the data extension socket needs to be close to an existing telephone extension point. Best of luck.