While I could make a mess of assigning telephone numbers, I want to make things as simple to understand as possible. With exception fo FSP Tower, there will be a more reasonable limit on the number of apartments. I will assume for 90 units, and the first 2 digits of the subscriber number will be the same for everyone in that building. For example, apartment 701 might get 4409. as their phone number where the highest number might get 4489. As you can see, the first 2 digits is the same, making for a limit of 100 numbers for everyone in the building including the public foyer, office, and employees. Not every employee will need their own dedicated telephone number, and most buildings will have just 3 employees.
As metnioend, the Tower is an exception to this rule. This is because each of the 30+ floors has more than 20 units on the floor. This is significant, and there is a need to make sense. With this in mind, the Tower will receive number from 0100 – 4399. Therefore, the next building with a limit of 100 numbers will receive 4400 – 4499. This manner will assure that every building will have the numbers they need. If there was a need to add new numbers, then this will be defined by me depending on the needs. Since elevators in Pennsylvania must have an active telephone line, I will assume that the elevator line has its own telephone number. In that regards, all elevators will be in the 99xx range of numbers. More information will be detailed in this section.