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How to make a Caller Identification Device ?

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Okada

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Hi

How to make a caller Identification for Landline ? What ICs I have to use to get the Caller ID ? I will be using 7 Segment displays to display the incoming phone number and also I will be using PIC microcontroller for the project.
 

Many answers in similar threads linked at the bottom of the page...
Similarly, searching Edaboard for keyword caller ID would help.
 
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    Okada

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I need DTMF chip in DIP package and I need to implement Booth Display.
 

The decoder gives 4 outputs Q1, Q2, Q3 and Q4. It gives hex values 0 to 0x0F. I will interface the 4 outputs to 4 inputs of microcontroller but how to read it ? I need to read the outputs and display the 10 or 12 digit(including country code) on the display. The problem is with reading. The decoder outputs change value very faste when a call comes and I have to read it fast. How to do it ? Also can I use this MT8870 decoder to display both caller and calling numbers ?
 

Ok. So, I connect STD pin to INT0 pin of MCU and when interrupt occurs I read the Q1 - Q4 data and store it in a array[] and later use it for display ?
 

Yes, that is correct but there may be a more fundamental problem here.

You are asking for Caller Identification, the designs so far are DTMF decoders, if you are looking to find out where a call originated from (the callers number via landline), a different protocol is used and it is also different from one Telco to another.

Brian.
 

I just need the caller and calling numbers to be displayed. What should I do ? MMT8870 works in my country. Can I use it for my application ? Same method of reading works for both caller and calling numbers detection ?
 

You can use the MT8870 or any other DTMF decoder to convert dial tones back to digits. My concern is how you know when the Caller ID signals are being sent as they have to be detected before the line is seized (handset lifted).

For example, in my country, the line polarity is reversed and switched back again then a carrier tone is placed on the line and the caller ID is then sent as 1200 bauds FSK, before the first ringing voltage is sent.

In some other countries, the data is sent as FSK between the first and second bursts of ringng voltage.

I do not know of any Telco that uses DTMF to send called ID because it seriously restricts the speed and type of data that can be sent.

Try searching for MT8843 and SIN227 for ideas.

Brian.
 

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