Hello!
We want to control users calls - we want to send the information about a making calls to the billing server online (Calling Number, Called Number, etc.). If there are enough money on the card, then user can make a call or drop it otherwise.
It should not be CDR, since it is created at the end of the call.
Users are living on Communicatiom Manager or Definity.
Do you know what kind of Avaya API components can do it, what kind of licenses I will need?

If calls are leaving or entering CM via SIP trunks, then an EDP app can be written to do what you want. You'd use the CMApi (aka the EDP call and media control API) to intercept the call, query your database to find out how many credits they may have, then time the call and drop if they run out of credit. You can also play warning announcements on the call if they begin approaching their credit limit.