At the carrier end: The Public Switched Telephone Network (PSTN) also referred to as the Plain Old Telephone Service (POTS) is a worldwide net of telephone lines, fibre-optic cables, microwave transmission links, cellular networks, communications satellites, and undersea telephone cables connected by switching centres around the world. This service allows any telephone in the world to connect with any other telephone in the world. When you place a call: The voice at your end is transformed into a series of 1's and 0's (binary code) until it reaches the other end and is changed back into a voice signal. This process has been the same method of delivery (binary) for telephone services since inception but is quickly changing as we enter the world of IP telephony.  IP telephony or VOIP (Voice Over Internet Protocol) in simple terms uses the internet to push calls over long distances. Take Skype for example, you log onto Skype and enter the number you want to dial, let's say Perth, the call travels by internet to a Skype destination point in Perth and initiates a connection to the PSTN network to make a local call. Because Skpe does this type of call alot they get really good rates which is why they can then charge you a rate for that call that would be much lower that if you had just called an STD number from your phone. This is why everyone thinks calls are more cost effective via IP telephony (VOIP). Th eproblem with this type of technology is that when your voice goes out over the internet it is less secure and also heavily reliant on your bandwidth available. Low bandwidth = Poor quality of call and in some cases drop-outs Though some calls will work extremely well this technology is still working out the bugs. Another issue with this is that most calls still need to initiate a call on the PSTN network which blends two technologies and creates more likelyhood of call failure. When the bugs are all sorted this will be a very solid platform to operate on.  The next session will be on delivery methods to your business that connect into the Public Switched Telephone Network and also more on delivery methods of VOIP. If you have any questions about telephony give ITELEC a call on 07 55 222 222. |