Public telephone networks are unrestricted dialing telephone networks that are available for public use to interconnect communications devices. This book describes the fundamentals of analog and digital telephone technology and communication and how the different types of analog and digital audio signals are described along with how their forms (PCM coding) differ in various parts of the world. You will learn about plain old telephone service (POTS) analog lines and integrated services digital network (ISDN) lines. The efficient GR-303 digital loop carrier (DLC) system is described along with how remote digital terminal (RDT) can allow a single communication line to provide telephone service for many businesses and homes. You will also learn how passive optical networks (PONs) are being used to deliver high capacity fiber optic communication to the premises (FTTP) communication lines direct to customers locations. The different types of switching systems are explained from circuit switched crossbar and time slot interchange (TSI) switches to packet voice and soft switches. You will learn how switches are interconnected with each other to form a global public telephone system. Multi-channel trunked lines are described including digital signaling (DS) lines, synchronous optical lines, and multi-channel optical (WDM) lines. You will learn how customers may lease lines or portions of communication lines for their own specific purposes. This book describes how telephone systems are controlled using signaling control messages, call processing, and SCP databases. You will learn about the different types of in-band tone signaling and of band common channel signaling system 7 (SS7). Also covered is how the public switched telephone network (PSTN) is beginning to use advanced intelligent network (AIN) to provide for advanced telephone service features. Explained are the key types of telephone voice, data, video and Centrex services. You will learn how customer care systems are transitioning from labor-intensive customer service representatives (CSRs) to services that are setup by customer self provisioning. Covered are the different types of digital subscriber line (DSL) including ADSL, ADSL2, HDSL, SDSL, and VDSL and how they connect the customer through digital subscriber line access modules (DSLAMs). You will learn that some DSL systems allow for the sharing of voice (analog) and digital (data) signals on the same line and how DSL data transmission capacity continues to increase to over 18 Mbps. You will discover why and how telephone system operators are converting their networks from circuit switched networks to packet voice systems. Find out how packet voice systems can offer the same or better quality of service (QoS) as traditional legacy systems.