Firstly, they want to save money. Secondly, they want to ensure that the users of their telephone systems, and perhaps more importantly, the people who call their company, get through on the first call. The telecommunications industry around the World is undergoing enormous changes. Countries are opening their markets to competition, which is allowing new companies to offer alternative services to their customer. However, it is important to understand how much money each type of service can save your company.
Many companies have offices in more than one town.
Staff in each of these offices will almost certainly need to talk to each other by telephone. PSTN stands for Public Switched Telephone Network. It is the basic dialled service offered by almost all telephone companies. An alternative to this exists which allows incoming calls to be routed directly to extensions. The advantages of DDI are that dialling between offices within a company is quicker and callers from outside the company who know the extension number of the person they want to speak to can call that person directly.