Yeah it is just full of racks and loads of wires that comes up from cables in the floor. There the cables, in a telephones case, are connected from the street to the digital side of the rack and thats where the link is between the street and the part that enables calls to go through.
The digital echanges are normally quite quiet, as opposed to an analogue exchnage where the "dialers" are making a load of noise for all the calls that are taking place at that time.