 on copper cabling. Providers initially replaced core toll switches (also called tandem switches in North America and transit switches in Europe) with Voice over Internet Protocol (VoIP) technology. One reason they replaced toll switches first, rather than Class 5 switches, is that there are far fewer voice switches in the core than in last-mile networks. Thus, costs are lower because there are fewer switches to replace and maintain. Class 5 switches, also known as local switches, are those that are located closer to customers than core switches. A small town might have one Class 5 switch, whereas larger towns with 40,000 or more residents might have two Class 5 switches. Carrier Networks Many Class 5 switches connect to a single, centralized switch in the core. In addi- tion, VoIP switches did not have the large number of features that telephone companies desired at that time. This is not an issue for toll switches, which primarily set up and tear down large numbers of calls between central offices. The Decline of Telephone Revenues and the Transition to VolP Service A major factor in the low investment in Class 5 switches is the decline in local tele- phone service. Traditional telephone companies have lost large numbers of phone wireline customers to wireless providers and cable TV Multiple System Operators (MSOs). This has led to lower profit margins on Plain Old Telephone Service (POTS). As a result, telephone companies have needed to develop strategies to invest in their mobile businesses and in high-speed data networks for enterprise customers. Rather than investing in new local softswitches, (VoIP equipment) while local circuit switches are still operational, they are transitioning to a more cost-effective, IP-centralized infrastructure for customers who have telephone service installed on broadband infrastructure. Although these centralized switches still do not have all of the 200 or 300 features installed on Class 5 switches such as Integrated Services Digital Network (ISDN) and payphone service, many 