When you upload a number to the directory you can choose the 'type' of number. This makes it easier to find the right info in the app. It also makes it easier for people to 'favourite' the right number in the app (plus you get a nice little icon next to them in the app).
Here is a quick rundown of the different number types:
Internal extension
The facility's internal extension number can be listed in the app (e.g. 4343).
If the prefix has been added for your account, the app will automatically recognise this and add it, allowing users to call internal extension numbers directly from their mobile.
External extension
An external phone number including the prefix.
Usually used for mobile numbers, other hospitals or external pathology or imaging organisations.
Pager
Internal/external pager numbers
Although you cannot page directly from the app, you can search and favourite the pager number for quick reference
Internal fax
If fax numbers are being used they can be specifically selected.
Entering a number as a fax means it can also be selected
When viewing a PDF article in the app, you can enter a fax number and send that PDF to the fax (kind of like a wireless printer).
Codes
A more general type of numbers, but could be a door code, printer code or some other similar piece of information.
Internal quick dials
Usually for those short numbers or phone numbers that can only be dialled from inside the hospital (people wont be able to call this number directly from their phone).