For the Telephone and Computer network you need 2 x Category 5e (Cat5e) cables to each single gang outlet. A Cat5e cable is a single cable that contains 8 wires that are grouped into pairs. For this reason it is know as 4 Pair. Each pair is colour coded as follows Blue & Blue/White, Green & Green/White, Orange & Orange/White, Brown & Brown/White. This cable can carry telephone or computer services. Now in reality the telephone network will only use 1 pair in a Cat5e cable and the computer network will only use 2 pairs in the Cat5e cable. So you can actually get the telephone and computer across a single Cat5e cable. However, if you do this you end up hard wiring the system and reduce much of the flexibility a properly installed system will give you. Since the Cat5e cable is cheap enough, you are much better off running 2 x Cat5e cables to each telephone/computer single gang outlet, one for each.
Additionally, you must remember to bring the incoming telephone line to the central location. The telephon eline will enter the house and be terminated on Master Telephone outlet. If you have the option, the best thing to do is get the telephone company to fit the Master Telephone outlet in your central location. If this is not possible, you will need to run at least 1 x Cat5e cable for each telephone line you have plus an additional Cat5e for Broadband from the Master Outlet to your central location.