Originally those 2 wires of the alarms auto dialer would have connected to a BT socket terminals 2 & 5. Terminals 2 & 5 correspond to the BT cable that comes into the house connected to line A & B at the rear of the socket.
If you had a older system, you will find terminal 3 was also connected when you pull the the front of the socket off. Terminal 3 is the bell wire for the telephone.
Moving foward as @joss say do you have FTTP and who with? However if you have an FTTP, the small ONT box will likely have a TEL 1 terminal, where you can connect you alarms auto dialer to. You will however need an RJ11 plug to do so.
Are the two wires a red and green twisted pair comming from your alarm?