organization's premises. PBXs route calls both within an organization and PON (Passive Optical Network) from the outside world to people within the Technologies deployed to extend fiber to organization, and vice versa. homes, businesses, and neighborhoods. PONs use nonelectrical devices located in PCMCIA (Portable Computer Memory the access network that enable carriers to Card Industry Association) dynamically allocate capacity on a single An industry group that has developed a stan- pair of fibers to multiple homes, buildings in dard for peripheral cards for portable com- a campus, apartments, and small and midsize puters. PCMCIA cards are used for functions businesses. such as modems and Wi-Fi services, and for additional memory. POP (Point of Presence) A long-distance company's equipment that PCS (Personal Communications is connected to the local telephone compa- Service) ny's central office. The POP is the point at Originally referred to 2G digital mobile which telephone and data calls are handed services that use spectrum in the higher off between local telephone companies, Glossary long-distance telephone companies, and the connected to the LAN. For instance, a proxy Internet. server in a VoIP environment ensures that external devices requesting to communicate POTS (Plain Old Telephone Service) with an IP telephone are who they say they Telephone lines connected to most residen- tial and small-business users. POTS lines are analog from the end user to the nearest PSAP (Public Safety Answering Point) local telephone company equipment. People Groups of agents that answer and dispatch using POTS for data communications with 911 and E-911 calls for their town, county, modems are limited in the speed at which or cluster of towns. They are often located at they can transmit data. police stations. POE (Power over Ethernet) PSTN (Public Switched Telephone A standard that defines how power can be Network) carried from wiring closets on floors to the The global network of circuit-switched tele- computers and other LA