A cellular phone and fixed phone call is prepared without any wires or viewable connections. That is really stunning gadgets particularly considering the way that they are basically modern radios. A cellular phone is a sort of two ways radios those demonstrations in the same route as a phone. However, normally a mobile phone is a great deal more mind boggling than a basic walkie talkie, as cellular phones allow two individuals to talk in the meantime, making calls and getting calls, three-way calls, call holding, voice mail, and text messaging. There are four stages involved calling processes which are pick up handset, press button waiting call and hand up handset (refer to Figure 1 in Appendix 1).
The first stage call processing is pickup handset. Scan control channel to find the closest base station to give it the most grounded sign and, in turn, after measuring signal strength, matching mobile to cell that has picked up the strongest signal possible connection. It checks 21 different control channels to determine the strongest available signal (Farley & Van Der, 2006). Managing handoffs or handovers, that is, moving from cell to cell is handled in a similar manner. The base station passing the call sends a hand-off request to the mobile switch after the signal descend below a handover threshold. After selected strongest signal, base station ping again to the caller and caller will receive the ringtone. If the person, the caller call available and can receive signal, the caller hears ringing sound. If the person the caller call busy or connection fail, the caller hears ‘tut’tut’tut’ sound. The other situation, if connection fail because of the number is out of service, the caller receive a voice message sent by MTSO such as ‘sorry, the number you have dial is not in service’.
The second stage call processing is press the button at the telephone, every number of channels has their own frequency known as ‘Dual Tone Multi Frequency (DTMF)’ (Mar, 2007). Pressing send or turning on the telephone passes information about the telephone to the cell site and afterward to the ‘Mobile Telephone Switching Office (MTSO)’ (Mar, 2007). Every digits number at phone key pad has different frequency. Two tones from phone keypad used to generate DTMF digits. One tone is chosen from four row and column tones. Row one have number 1, 2, 3and 4. Column one have number 1, 4, 7 and *.Example according Mar (2007),combination frequency from column 1 and row 1 which is 1208Hz and 897Hz will produce DTMF digits number 1. Combination frequency column 3 and row 3 which is 1477Hz and 852Hz will produce DTMF digits number 9.
The caller enters a codes of 7 or 10 digits a telephone number and presses the send catch. Mobile station scans the band, looking for a setup channel with a strong signal, and sends the data phone number to the nearest base station using that channel. Base station relays the data to the ‘Mobile Switching Center (MSC)’ (Forouzan, 2007). The MSC sends the information on to the telephone central office. On the off chance that the called party is accessible, a connection is made and the outcome is transfereed back to the MSC. At this point, the MSC allots an unused voice channel to the call, and a connections built up. The mobile station automatically adjusts its tuning to the new channel, and communication can begin.
A call gets checked with all this information. There are many parts to each digital message. A three digit code called the home system ‘identification number (SID)’ (Pryke, Kaing, & Lee, 2015) identifies the cellular carrier phone is registered with. For example, Cellular One’s code in Kuching, Sarawak is 082. The cell phone now transmits a very short message (about 0.25 second) that contains the ‘Mobile Identification Number’ (Pryke, Kaing, & Lee, 2015), it’s ‘ESN (Electronic Serial Number)’ (Pryke, Kaing, & Lee, 2015), and the number you just dialed. If the number dials successful connection, the caller hears caller ringtone.
The next stage call processing is waiting call. The called subscriber answers the call and the MSC informs the mobile that the call has been replied. The call has entered the discussion stage. The speech path has been setup between the mobile subscriber and the land-line subscriber. During the conversation the subscriber receiver another call and hears the caller ringtone which is sent by MSTO. This process take few second, depend to the person that user call. This process involves sending an audible signal to a party engaged in a phone call when the user receives a second, incoming call. The process call waiting occur when the service enables the mobile subscriber to be notified of an incoming call during a conversation.
For example upon receiving the signal, the subscriber has the option to either select to take the second call or reject the incoming call. Besides that, the subscriber also takes places the first caller on hold by pressing a button on the user’s phone. So the second caller receives a busy signal or is exchanged to a voice message framework in which the second caller is educated that the client is no able to take the call and welcome to leave a message on a recording. There are a number of variations on the fundamental call holding up highlight. These varieties by and large fall into one or both of two sorts of procedures. In one, the user is given different manner choices to direct the second call. In the other, information is given to the user concerning the personality of the second caller so that the user can decide how to handle the second call.
The last stage call processing is hand up handset phone. The call release is a process in which the caller terminates the call. For example this process happen either one of the subscribers hangs up the phone. After that the information sent to radio base station and subsequently to MTSO process the initiated call release. MTSO sends the tone where it different from the first step when the subscriber pick up the handset. The public switching telephone network (PSTN) informs that call release has been completed at its end and RBS stop send the user information channels and now it is in a normal condition. Cellular users also stop the transmission of information and try to get the best control channel on a cell.
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