nnect- ing two of your offices, the local telephone companies at both ends may provide the local leg or local loop (mean the same thing) of the circuit, even though you are billed by the long distance com- pany. Sometimes long distance companies rent circuits from each other. Some calls may still be transmitted by bouncing the sig- nals off of communications satellites. Transponders on the satellite may be shared by different long distance companies. The trend is away from satellite communications as the use of fiber optic cable becomes more widespread and its resulting capacity to handle call volumes increases. However there are still remote areas re- lying on satellite and microwave radio communications. Long distance companies generally refer to their network, which is the collective group of all circuits over which calls are The Telecom Handbook 38 277 UNDERSTANDING THE INDUSTRY sent or permanent point-to-point connections are made. The net- work may include a variety of transmission media including copper cable, fiber optic cable (underground and above ground), and to a limited extent, microwave and satellite communications. The network also includes electronic hardware to provide the media with the capability to transmit. Long distance carrier networks have electronic switching equipment for connecting and routing calls, enabling a large num- ber of people to access a common group of outside lines or circuits. These long distance company switches are located at what is sometimes referred to as the carrier POP, meaning point-of-pres- ence or the NOC (network operating center). You may reduce your costs by having a circuit that connects your telephone sys- tem directly to this POP. The circuit may be rented from the local telephone company by the long distance company, although you will probably be billed for it by the long distance company. The cost of this circuit is called an access charge. Smaller companies and residences reach the long distance carrier networks in most U.S. locations through equal access