Getting info from the PBX is just done by retrieving the sets, this is a snap shot of the Sets in the Database of the PBX. This can be done in hours but depending on the size of your switch could take a long time. The idea of telephony manager is to provide a GUI for the set management. Then the TM Directory part is when you do your initial CND sync it takes the CPND an the DN from all the sets and creates the directory so for example:
a set with a number of 1000 and a name of John Smith would create a new Directory entry "JohnSmith" with a first name "John" and a Last Name "Smith" a CPND entry of "John Smith" a DN "1000" and ESN "01000" (default for ESN is to put a 0 on the front)
After the intial create you would then use the TM to do the changes and sync back to the PBX eg.
John leaves and is replaced by Bill Gates go into the TM Directory and create the new entry for Bill. Then go into the Set 1000 and change the directory entry to the new one, go down to the Key 0 where the Name is and there is a button to copy the CPND from the Directory, click it "Bill Gates" is filled in. Save the Set and the select the check box by set 1000 and transmit to the PBX. Go into TM Directory and Delete "John Smith".
All this can be do in Hours, all the changes on the TM will not affect the users, until you TX to the PBX. There is a check box that stops the transmit if the user is on the phone if you TX without this checked and hes on the phone the call would be droped.