Two Ways To Dial A Telephone Number example essay topic

There are two ways to dial a telephone number. Both ways accomplish the same goal: to send a signal to the central office that we want to be connected to that number. The first way is rotary or pulse dialing (rotary dialing was patented in 1923 by Frenchman Antoine Barna y). This method of dialing sends a signal to open and close a switch at the end of a local loop at a fixed rate of speed. These pulses are translated into numbers by "counting" the number of 1/10-second breaks. Dual Tone Multi-frequency (DTMF) is different in that the number is dialed by sending a specific dual-frequency tone assigned to each number.

That assignment is determined by a grid. The different high frequency tones (three) are assigned to the columns on a telephone keypad, while the different low frequency tones (four) are assigned to the rows. Each number will then have a specific tone created with the two tones that correspond to that button. See picture below. Wide Area Telecommunications Service (WATS) is a communication service that is primarily geared towards business since they generally have a large volume of telephone traffic. There are different pricing options.

Historically, one way is to price by region or zone, so if your company only called to the South Central region (TX, LA, AR, OK) and you were in Texas, you were billed less than someone who called to this same region, but was based in New York. There have been pricing practices changes since divestiture in that there may just be a discount per minute instead of basing the pricing on regions. A leased line is just a direct connection between two facilities and is usually charged on a distance basis. The further apart the two facilities are, the more it costs to lease the line (s).

The Private Branch eXchange (PBX) lets a company use its own phone system as a mini-central office. Internal calls can be routed through the phone system software and hardware and never go through an external phone line. External calls can be routed differently, according to rules set-up in the phone system. At our office, we use a Least Cost Routing (LCR) software that determines the best line and route to use depending on the number called, time of day, etc.

This software is supported by our phone vendor and is update quarterly. Centrex is different in that the central office is acting as the office's exchange- or in our case Centrex would take the place of our onsite telephone system. All the routing would be done at the central office. This type of set-up would be best for a small office and would help defer the cost of an expensive phone system.

ISO-OSI Layer Model.