Telephone Billing machine!!!

[Shahriar]

Hi to everybody

I plan to build a device that many of you may have thought about it before. (or may have heard about it )

The project is to be connected to telephone line. then when somebody hangs up
the phone, he is not able to dial a number till he dial a specified number (i.e. 1111 for Person#1)
then the device will allow him to dial his number. during his conversation the device calculates the money and
saves it to Person#1 bill. every person have a password (i.e 2222 for Person#2). then at anytime the device can specify how much
money should every person pay.

Two important problems with the device are:

1- I want to connect the device to telephone line in parralel. the how I disable person in Number dialing before he Enter his password.
If I want to connect the device in series then I have to place the device at the Home Telephone lines  Entry which sometime is very difficault specially for Institutes and departments.

2- How should I calculate the bill during conversation? Do telephone center sends pulses on telephone line to calculate the bill? If yes, How to Detect those pulses?


ThanX in advance
Shahriar

 

[audioguru2]

How are you going to calculate how much to charge for long-distance calls? Detect the dialed area code and compare it to a list?
Maybe your telco charges you for local calls. In Canada I can make as many local calls as I can, for any amount of time, at no extra cost.
If I want to make a free not too far long distance call, I dial a local beer company or newspaper, hear a short commercial and use their network to make my call.
I think your system would bill me for my free calls.

 

[ECET0purdue]

you could detect the pulses with any computer device if you plan on using a computer then program it to count when the input recives a signal and stop counting when the signal goes low. then just X the time by money..... i hope it is ok to give links... but i used a company called measurement computing and you can get a device there that could do this.... iam sure there are different ways and maybe even better but i just like programming the computer interface devices... cheers...

 

[Shahriar]

Hi

So I think I guessed true. during a long distance call, I will receive more pulses during a minute! (Am I right?) {Dear Audioguru, if this is right, then it is how I am going to calculate the money!!!)

2- Do anybody know anything about the amplitude of these pulses?

ThanX in advance
Shahriar

P.S. I think you forgot to write the LINKS

 

[audioguru2]

What pulses?
In my country, a long distance call sounds just like a local call without any beeps or pulses.

A phone system in a hotel senses the "1 plus area code" at the start of a long distance call, waits for the call to be answered when the telco's battery voltage to the hotel's phone line gets a momentary interruption and starts a timer. When the call is finished the telco's battery to the hotel's phone line has another momentary interruption when the distant party hangs-up, or the phone line's voltage goes high (or current goes to zero) when the hotel user hangs-up. Then the timer is stopped.
The computer in the hotel's phone system calculates the total time, the cost of the long-distance call and multiplies it by 100 for your bill. ;D

Multiplies the cost by 100? Sure, a long distance call from a hotel here is about the biggest rip-off around! ;D

P.S. What links? I learned this stuff when I installed and programmed big phone systems for about 10 years. 8)

 

[ECET0purdue]

hope this works... for you or at least helps its the chart for the phone Feq.


http://nemesis.lonestar.org/reference/telecom/signaling/dtmf.html

 

[gvvineet]

you can detect the pulses by using modem ; i think that! i am just in second year of diploma engg. so i doesn't no that it is right or wrong. but i want to suugest you . you can  calculate the bill using computer by giving him the information about the billing in detail , i.e. area code of caller & receiver both , in 1 call how many pulses are permitted by the telecom company & the time spend in that call. please forgive me if i am wrong.
                    thanking you.
                                                                                    yours friendly
                                                                          vineet vijay gajendragadkar

 

[kid_kv]

hi,

Look at a DALLAS MAXIM Microcontroller " MAXQ3120 " becoz i just got a thing in the mail from them and it looks like waht you need.
go to ther web site and see if it is what you need  :

steven 8)

 

[MP1]

when somebody hangs up
the phone, he is not able to dial a number till he dial a specified number (i.e. 1111 for Person#1)
then the device will allow him to dial his number. during his conversation the device calculates the money and
saves it to Person#1 bill. every person have a password (i.e 2222 for Person#2). then at anytime the device can specify how much
money should every person pay.

Here is an interesting thought... you could put these numbers on a card and call it a calling card....

Hmmmm...has some familiarity to it....  ;D
You sure this hasn't already been invented?

MP

 

[Shahriar]

ThanX all for your replies.

Dear audioguru, I didn't say that long distance call sounds different. the pulses which I have heard about them is on both local call and long distance calls and you are not able to hear them. as I said I am not sure about this theory.

I ask the question in another manner:

Imagine you are asked to build a telephone with a smart card. the telephone should decrease the person credit which is stored in the smart card. this is different depending on the distance he/She has called. (Japan or India).
How do you calculate the money which you are going  to decrease from the person credit????
This is what have built and you see it every where over cities.

ThanX
Shahriar

 

[audioguru2]

Hi Shahriar,
I don't know what the "pulses" are that you are talking about. There aren't any pulses on telephone lines in North America except rotary dialing pulses, and the pulse from the telco when the distant party has answered, and again when the distant party has hanged-up. These two pulses are a disruption of telephone line current and certainly are audible as a loud "click".

To make a telephone with a smart card your telephone decodes the dialed number and looks-up the charge per minute in its memory. The telephone starts its timer when the distant party answers and stops the timer when either party hangs-up. The charge of the call is calculated and deducted from the amount on the card. ;D 

 

[ante1]

Hi Guys,

If you want to go deeper into telephones here is some info for you: http://www.electronics-lab.com/forum/index.php?topic=4014.0

 

[Shahriar]

Dear Ante, Than you for your link. I will check it.

Dear Audiguru
the theory you said looks a little bit strange and if telephone designers Have done such a thing then they have challange a big problem.

Imagine that ten years have passed and the goverments have decided to increase or decrease the telephone bills. they they have to upgrade thousands telephone memory over a country.

I beleive smart card telephones uses another theory.

ThanX a million
Shahriar

 

[sofian]

I'm interested in this idea too, just to make it easier to calculate charge based on country and talk time in my callshop.