Upgrading an old camera system

[Farmer Ted 0]

We have a very old camera installation in our shed which I would like too upgrade, if possible.

There are 3 camera points in the shed which use rj11 sockets. They feed into the central distribution box as shown in the image.

Apologies for the lack of clarity on the images but it was dark when taking them image and the location was a bit precarious.  I am unable to confirm what type of cable is being used. Can you tell? 

The thick cable coming out of the box goes into the house where I believe it terminates with composite connection.

Is this cable still useful for a modern camera setup? For the setup I want good image, sound and the ability to view via Internet.

Pan and zoom are optional but I'd like to know if this cabling is suitable for a modern setup before I start looking into the hardware side of things.