Solution to the conflict in the traffic of telephone calls in Mexico

This prototype aims to resolve the conflicts that arise in the traffic of telephone calls at the house-room level and of a micro-enterprise by developing a system capable of:

Detect who makes long distance calls Estimate the telephone cost and cost of an online call and be able to verify it with the telephone receipt Restrict telephone calls in a dynamic way Restrict the time of telephone calls List the telephone number Long distance dialing, date of completion, time, duration, cost and who makes the call. Count local telephone calls, both in quantity and duration in total minutes to make a comparison with the measured service.

Every project is generally the result of observing or analyzing a need and this was no exception. The device called a system for the measurement, control and supervision of telephone calls is the result of analyzing which companies in Mexico are the ones that generate the most complaints about the services they provide.

Historically, the company that has had the most complaints before the Federal Consumer Prosecutor's Office, has been TELMEX in the provision of telephone service to common subscribers (PROFECO, 2003-2006), problems such as calls that were not made, wrongly calculated times and LADA not authorized, generate unnecessary expenses for a company, even in common subscribers where they can have a significant amount, without having a reference standard that can be used in case of claims or clarifications.

Based on a market study, in Mexico there are practically no solutions for the control of a single telephone line that respond to the situations mentioned above. The systems that exist offer mechanical-electronic locking padlocks to complex metering and charging equipment for the control of several lines and their extensions. Therefore, a team was designed and manufactured that can respond to the problems of potential customers (micro-users) and can make an investment based on their possibilities (market study).

The most frequent problems that have been detected are: registered calls that the user did not make, unauthorized long distances, excessively long calls, abuse in personal calls, calls to unauthorized 900 numbers, telephone dialing errors; which has generated unnecessary expenses for the users of the telephone service, without having a comparison standard that can be used to measure and control their telephone line.

Analysis of demand

Currently in our country more than 18 million telephone lines are installed, of which 75% are residential (house-rooms) and 25% are commercial, of these, 95% correspond to micro-enterprises, which gives us a potential demand of 14 million common subscribers, and 4 million non-residential users, of these together it is estimated that around 70% do not have a protection system (feasibility study)), which translates into 12.6 million customers of which according to Baca (project evaluation 2001, p 97) should be considered only 10% of the potential demand to have an estimate of potential customers, which gives us 1.2 million who could potentially demand the product under study.

Based on these problems, it is believed that a simple and inexpensive pricing system can help eliminate them.

DEVELOPING

The following points detail what was achieved in the design of the prototype:

1.- Operation characteristics

Principal functions:

Compliance with the standards requested by SCT for the adaptation of any external device to the telephone line, thus avoiding charging "the commercial line. Ability to handle a single telephone line and its extension. Storage of the dialed telephone number, date of completion, duration and extension line from where the call was made; as well as the cost of the call, being able to make the backup in a time that will depend on the telephone flow and the memory capacity of the acquired system. Visualization of the dynamic cost of the call during the call, and the estimated cost of the monthly billing of the telephone service.Storage capacity from 200 to 6,000 phone calls Easy data transfer to larger computer systems for processing, printing, statistical representation and storage on floppy or hard disks Programmable control of the output of phone calls allowing restrictions on calls from Unauthorized LADAs. 3-digit custom access key to allow calls with entry through the system's digital keypad. Programmable restrictions on the duration of a call, whether it has been made on site or corresponds to an answer.Count of local telephone calls, both in quantity and duration in total minutes, for the measured service function.Backup power supply that allows it to operate even with loss of electricity from the commercial line allowing it to be used as a portable system Detection and notification of loss of telephone line Possibility of dialing the telephone number from the system itself, using either dialing by tone or pulse. Presentation of the dialed number by means of a 12-digit display to prevent dialing errors. Telephone directory storage of up to 25 16-digit telephone numbers with the possibility of abbreviated dialing. 120-second direct recording of messages. make annotations using the keyboard.Possibility of dialing the telephone number from the system itself, using either tone or pulse dialing. Presentation of the dialed number by means of a 12-digit display to prevent dialing errors. Storage of the telephone directory of up to 25 16-digit telephone numbers with the possibility of Abbreviated dialing. 120-second direct message recording. Easy to make annotations using the keyboard.Possibility of dialing the telephone number from the system itself, using either tone or pulse dialing. Presentation of the dialed number by means of a 12-digit display to prevent dialing errors. Telephone directory storage of up to 25 16-digit telephone numbers with the possibility of Abbreviated dialing. 120-second direct message recording. Easy to make annotations using the keyboard.

Status indicator functions

Visual indicators of the restriction mode Detection of telephone line loss Fill graph of the system's call storage capacity Audible alarm answered and every 5 minutes elapsed.

Physical and electrical characteristics

Microcontroller based system LCD screen Membrane keyboard 9 volt 300 mAmp adapter (not included in the prototype) 20 minute power line loss backup power supply system data backup for 14 hrs. due to total loss of general power supply. Overvoltage protections in the telephone and power lines. Weight not greater than: 500 grams. Dimensions: 20 x 12.5 x 3 cms.

The aforementioned characteristics were defined seeking to design and manufacture an ergonomic product, with low power consumption and with cutting-edge technology.

2.- Project engineering: Process

The digital telephone call controller (CDLT) was divided into two main parts:

Hardware.Software.

Hardware analysis

The Hardware that was used is explained in the following diagram.

Figure. 1 Block diagram of the elements used

Block diagram of the elements used

Given the complexity of implementation, programming and memorization that the system presents, a microcontroller from the 51 family was chosen for its control, specifically the 8OC31 (Embedded, 2000) due to its best programming alternatives; One of its notable characteristics that decided its use is that it presents low power consumption given by its internal circuitry, compared to others that demand up to three times the energy than this one. Its price is notorious compared to those of its same family, the 8OC31 can be worth up to 2 times less. It does not have internal program memory, so it needs to connect an external memory and thereby “sacrifice” 2 of its 4 ports. The microcontroller is the one that governs ”our system and is the“ springboard ”for communication with the other elements. Source:Own. 2006

The choice of the program memory (ROM) was made based on the ease of erasing it and its handling capacity; One of the type "EEPROM" 2864 (Semiconductors, 2002) was chosen, which are electrically erased memories, compared to the "EPROM" 2764 (Semiconductors, 2002) that are by ultraviolet light, the former can be erased directly from the programmer, while that the latter require an external device to be cleaned (Memory, 2003). In terms of price, the "EEPROM" type are a little more expensive, but their gain in terms of time reasonably justifies their use. Although a microcontroller with internal program memory had been chosen, this would have had to be changed, since the CDLT program requires 8 KB of storage space and it offers a capacity of only 4 KB.

The external data memory is a 16 KB RAM; All the information generated by our telephone flow system is stored in it. The required capacity will depend on how much information is being worked on, (being able to extend at our convenience logically with a maximum); if this memory loses its energy, the data will be erased and cannot be recovered (Memory, 2003).

The internal data memory that the microcontroller has has a capacity of 256 Bytes, which is why it was used for direct operations with the program memory, while the external data memory is dedicated for the exclusive use of information from the phone.

Three forms of communication between the prototype and the user were observed: a printer, a computer and the LCD screen, deciding on the latter is already more difficult for the user of the product to connect a computer or printer to obtain the information required from the system, while with the screen you can explore it at any time you want, without having to connect it to something extra for your operation. The LCD screen is of the matrix type (The reasons that were taken to use it were considering display factors, price and size), with the relevant characteristic that it has its own integrated controller. It is a matrix that has 32 characters distributed in two lines, where each of these is 5 x 7.

The keyboard used is a touch sensitive membrane. This was chosen to be able to manipulate the size of the keys and their location in the system. It is of the 4 X 4 matrix type with high touch sensitivity, being the programming interface between the user and the system.

Backup power based on rechargeable batteries has its main justification in places where there is loss of energy, if there is no backup power and the power goes out, both the system and the telephone stop working; Two batteries are considered for its operation, although with one that it has, it can continue to operate. For example, if we have a battery of 400 milliampers / hours mA / hrs.) The system can work up to 2 hours. If we have two, 4 hrs. The batteries you need are 9 volts (Belove, p 55).

The choice of the electronic lock, (which disconnects the telephone from the line) is based on its ability to switch and its power dissipation, since it normally has to be "closed". So that the telephone line is operating. Different types of SCRs, relays and Optocouplers were seen, deciding on an optical device because it was faster and the one that generated less heat (Optoelectronics, 2002).

The interface circuit between the telephone line and the system is with LSI characteristic and CMOS technology for its fast communication, in addition its useful life is higher compared to TTL. These are a bit more expensive, but their benefit supports them (CMOS, 2001). The digital recorder that is included is totally optional, it has an EEPROM memory and includes its own programmer, which allows it to work independently. For sound coding, the recorder uses the sampling theorem, which has high operating efficiency, as well as operating at low power. An integrated power amplifier is added to give volume to the message, and this in turn can be varied (Memory, 2003).

The prototype is physically shown below:

Assembly of the main board and the display.

System main board

Final System Prototype

CONCLUSIONS

The personal and professional reasons that motivated me to develop this project were, in Mexico it is generally expected that developed countries will give us the solution to technological problems; foreign companies come, analyze the areas of opportunity, develop them and we are only marketers and consumers, which generates a dependency, resulting in no sustainable development in our country. It is for this reason that the innovative capacity and creativity of Mexicans for the development and solution of machinery and equipment must be taken advantage of and recognized, which will allow us to generate more jobs and achieve a reduction in their production costs.

I believe that in our country there is talent for the development of technology, but we have not given it the importance that it has, many projects remain on paper and probably do not transcend, especially because designers do not know how to sell it; How many projects are in the research centers generated by illustrious teachers or doctors, but unfortunately many have not permeated society.

BIBLIOGRAPHY.

Auronix. Call rate system, text available at http // www.auronix.com / s / raters. Accessed October 8, 2006, Baca U. Gabriel; Project evaluation; Mexico, Ed. Mc Graw Hill, 2001. Basic Telephony; Sweden, Ed. LM Ericson Telephone Company. 2000. CMOS logic data; USA, Ed. Motorola, 2001. COFETEL. Telephone density, text, available at http // www.cofetel.gob.mx / wb2l / COFETEL / COFE_densidad, accessed on October 5, 2006, Delsatgroup. Telephone Controller CT-8002, text available at www.delsatgroup.com/principal.html; interntet; Accessed November 5, 2006.Embedded Controllers; USA, National semiconductors, 2000. INEGI. Density of telephone lines in service 1999-2005, text available at http // www.inegi.gob.mx / est / contents / espanol / routinas / ept.asp? t = tinf1268 = 3556; Accessed September 12, 2006.Indin, P. A , “Intelligent Pone-Line monitor”; Radio electronics, March 2004.