Telecommunication Systems Rotary Signaling

telecommunication systems Rotary signaling is a way of dialing with the use of electric pulses corresponding to the number being dialed. It is used on the older versions of telephone units. DTMF is a way of dialing with the use of different frequency tones corresponding to a number being dialed. It is now widely used in the modern telephone units.

WATS is a telecommunication service that provides outgoing calls, incoming calls, or both to a subscribing customer. This service allows communication between stations at a certain fixed rate for OUTWATS and toll-free for INWATS by dialing a specific phone number. A leased

line is a communication service that is permanent between two communicating stations. Leased lines do not need phone numbers to connect, and are private lines usually used for offices for voice or data communications.

PBX is a device used as a switch to multiple lines of communication within a certain area to a single public telephone line. PBX used by companies to minimize the amount of public telephone lines being leased to save cost. Centrex is like a PBX in a sense that it also provides switching between multiple lines. However, PBX used by telephone companies for their central offices instead of customer use.

The 7 layers of the OSI model are:

1: Physical - The lowest layer of the model, dealing with physical and electrical specifications.

2: Data Link - 2nd layer, provides procedures and functions for data transfer between network devices

3: Network - 3rd layer, performs routing of data in the network.

4: Transport - 4th layer, handles the control of the data transfer by controlling the data flow and performing error correction.

5: Session - 5th layer, controls the connection between communicating computers over the network.

6: Presentation - 6th layer, handles the transformation of data for the application layer to understand the information.

7: Application - The highest layer, it is the layer that interacts with the user of the computer through software application.