The way to run cable between floors depends on how the house walls are built ... in some cases, it is easiest to drill into the wall top plate from the attic & then drop down a fish tape, pull the cable up, run it to where it needs to go, drill the top plate again, drop cable down, fish it out
This does however, require relatively accurate measuing of where the wall plate will be & where the walls are, say in relation to the attic stairs.You can also use a very specialized drill bit, called a "Diversibit" ... most electrical supply house have them .. it is a bit with either a normal tip or a woodbooring drill tip .... it is about 3 Feet long on average ... you can also get an extension for it ..... it works with a special holder to
keep it centered in the wall stud cavity ... it also requires a Variable Speed Reversible Drill .. once the bit comes thru where you want it, attach a pull wire to the hole in the end of the bit & use Reverse on the drill to bring it back up ... secure your cable to the pull wire & pull it from the other end
Now you can see why techs can charge $70 or so per Connection Point, with Materials Extra ... in some cases really easy (walls are not plastered) or it can take a lot of time
Some info on Diversibit: (home depot also carries them, at least in NJ area)
http://www.tselectronic.com/greenlee_pr...ssion=6a7ecca96aebe098e0d3cd2e467355b2