Caller ID Identification with picbasic

[vstudio3k]

Hi all,

My group is working on telephone remote control. We built a devices installed in telephone line from residential house that can turn on certain things around the house such as light, tv, etc. We have a few problem right now such as caller ID detection.

We can get signal and decode with (DTMF: MT8870) and microcontroller (PIC16F84A). Our device pickup the phone after 3 rings and able to turn on various things now. We are trying to write a code receive caller ID, so microcontroller can pickup the phone automatically, but we are not able to find any valuable information to finish it.

Please help us

 

[csaba911]

Try this, might help.

http://www.hackcanada.com/blackcrawl/telecom/cidspec.txt
**broken link removed****broken link removed**

Csaba911

 

[eblc1388]

You do not have your location filled in. It is often a great advantage to indicate the country one lives as most problems involves solutions that is particular to a certain locations.

Different parts of the world telephone system uses different means to send CallerID. If you are lucky, the caller ID might even being sent via DTMF (Brazil, Belgium, Denmark, Finland, Iceland, India, Netherlands, Saudi Arabia, Sweden & Uruguay) and getting at it will be easy.

However, in most telephone exchanges, that information is sent via 1200 baud modulation at the beginning of the ring signal or between the first and the next ring signal. You will need an analog interface circuit to tap out the information from line and then decode it using your microprocessor.

Another method is to use a stand alone caller ID display unit where it can be bought cheaply in most high street shops or eBay and use its interface or even decoding circuit. You just need to tap out the data stream which is already in serial format. It is illegal to connect your circuit directly to the telephone lines so such data tapping usually use an opto-isolator to isolate the called ID unit output signal and your circuit. The following is an example:

BT CID unit and converted it to RS232

You will also need to search for the data format of the Called ID data stream so you can isolate those bytes you wanted.

Edited: The link for author "Jon Payne" inside the above quoted link do not work anymore. This is another link on the same subject for hobbyists in UK only. **broken link removed**

Also this FAQ: all you need to know about Caller ID

 

[vstudio3k]

Thanks for all responses. I finds very helpful on the response from eblc1388 . We can't get any signal from MT8870 for now. I will post some problems as well as solutions for our device soon. Thanks again...

 

[vstudio3k]

I know US use HFK instead of DTMF. I installed one chip "HT9202C operate 4MHz" found from broken phone to use in our device. I captured some binary number (alot ex: 0000000011111110101101010) from pin DOUT, and I have no idea how to decode them. Our microcontroller operate speed change to 20MHz. I am not able to decode these series numbers on first and second ring with speed operating 5 time faster than the HT9202C. How to decode them. Please help

datasheet HT9202C
doc.chipfind.ru/pdf/holtek/ht9202c.pdf

 

[philba]

from the datasheet, that's a tone/pulse dialer. I didn't see anything that dealt with CID.

There are modem chips that know CID. It runs in my mind that it's part of the Bell 103 standard (or Bell 212?). So just about any modem chip should handle it. Even really old ones...

 

[vstudio3k]

The broken phone built in caller ID, answer machine and other options. They must use this to decode HFK signal send out from pin DOUT. I captured some binary numbers (2 pin from this chip: CLock & DOUT to microcontroller and a tip connect to pin HFK). Is this connection right?