Posted by: Ghulam Abbas
Posted on: 20 October 2014
In past people use landline or wired system for communication. But that is not a satisfactory way to communicate. So after landline, wireless system was introduced that operates on radio frequency. This wireless system usually used in military operations and local radio stations. But this has a disadvantage that the range of systems operated as wireless control, is very small. So, this type of system also cannot be used for large distances. As technology advanced, we are able to control our appliances through one place. So overcoming this problem, wireless system operated by GSM mobile network was introduced. This one system has a lot of advantage, that for large distances, any appliance can be control through the use of GSM network and DTMF (Dual tone multi frequency), without using microcontroller. Practically it reduces circuit complexity as well as it shows better results.