| A | B |
| Transport area | The designated geographical area where Local exchange carriers also known as local telephone companies provide service |
| Local Loop | a loop of copper wire that allows current to flow from the telephone to the central office and back. |
| Demarcation | the point at which the responsibility of the service provider ends. |
| Local Exchange | Also known as the central office this is a group of local systems inter-connected by one carrier. |
| Ocean Networks | optical fiber cables underwater connecting continents and countries together. |
| Core/Long-Haul Networks | responsible for transporting large amounts of information from the metro and regional networks in one part of the geography over very long distances |
| Telecommunications | the flow of various types of information from a variety of sources over a variety of transmission systems to a variety of consumers |