When the first mobile phones hit the market, many people were amazed at how advanced their technology was. In fact, it was just amazing that a very small communication team could send and transmit voice messages. It was clearly more advantageous than a two-way radio that was all the rage in those days when you can only call your base stations and other radio phone users linked to your channel. Most of those people using two-way radios were hobbyists or company employees with a base to contact field employees to monitor their whereabouts. The advantage of a mobile phone compared to these two-way radios was the longer range power of a cell phone, while a two-way radio has a limited operating range.
At this stage, however, mobile phones, although already using cellular technology through channel reuse, were still considered to be in their early stages, since the operator used is analog technology. But first, so that you can better understand how a mobile phone works, let me explain the term channel reuse. You see, radio signals operate on a particular frequency. These radio signals, to be free from interference, must operate on a different frequency. Just like if a certain radio frequency is on 120 MHz, another radio frequency must be on another frequency to avoid mixing signals with the radio signal that is already operating on the 120 MHz frequency. But in the case of phones mobile phones, many of these units work on the same frequency, through the principle of channel reuse, which makes mobile phones used by many people. Channel reuse was made possible by providing limited power to each mobile phone unit and providing many cell sites or towers. Therefore, a mobile phone can relay and receive signals only to the nearest cell site or the nearest tower and not affect another cell tower in another location, which makes it possible for other cell phones on the same channel to send and receive signals. at other cell sites. or towers without interference.
Now that you have a good idea of how the cell phone works, let’s go back to the first carrier used by mobile phones, which is the analog system of transmitting radio signals. These types of radio signal carriers are the uplink and downlink frequencies of radio transmissions that were used in all forms of radio messaging before the advent of digital technology. A very good example of these signs can be seen in hospital operating rooms that are usually shown on television and in movies showing the near death of an individual, as shown by the up and down movement of a light in movement on a monitor graph. The up and down light you see moving is an analog signal frequency that represents the sound of a patient’s heartbeat.
When digital signals became available for use in radio communications, it was found that the channel reuse system employed in mobile phones is more suited to the use of digital signal transmission systems, since digital signals are not susceptible to interference unlike analog. Thus, telecommunications companies soon began to rebuild their signaling system to adapt to the digital signal delivery system in mobile phones.
It was at this stage that a communication company in England was able to develop a digital communication system known as Short Messaging Service or SMS for use on cell phones using the digital signal delivery system. By the way, SMS can only be possible with a digital operator, but never in the old system that was the analog operator. The development of SMS or text massage capacity of mobile phones was actually designed to be used by the deaf and dumb segment of the community. But now we know what happened to this type of communication intended for the deaf.