Well guys, I know you sometimes want to test your work before the customer moves in and the cable is connected but DVD players and scanners are not the answer.
You are going to have to wait until the actual cable signal is available. The reason for this is your "system" needs to be designed around the level supplied by the CATV drop and it's not a given that it will be the same from house to house.
If you don't have the equipment to determine signal levels simply run and terminate your runs and let the cable company handle the connnections at the home run location.
They will probably want to connect only those runs that actually have a set connected to them anyway so if you install a bunch of splitters to make all jacks "hot" it will likely be a waste of time.
-Hal