It is the business practice of sending all clients' billing info to a separate company, who then does everything for you. It also allows a company to cut down on time and human resources spent on administrative tasks.
Direct Inward Dialing Support. This function is offered by telephone companies with the goal that ATC clients could connect all range of company numbers to one or several lines. The aim is to give a personal number to every employee without having to connect it to a separate phone line. Thus, all telephone traffic can be divided and controlled more efficiently.