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Vignesh Prasad
01/16/06 22:22
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#107554 - Simple yet stupid
Hi all, I am happened to come across a project, which is really simple and got Rs. 75000(~$1700) as cash prize in a competition.

The concept is simple: Generally in landline phones, the number of rings can be used to convey some sort of info:

If two rings mean some info, if three rings mean another info, (if the callee understands).

Based upon this idea, a student has designed a project:

Both ends will have a 89C51, and DTMF dialer, LCD and Keyboard. You could type some 100 characters as sms, and give the destiation number in the node 1.

The MCU dials the destination, does some handshaking, and then conveys the ASCII as specific number of rings. The destination MCU 'understands' this, and decodes the SMS, displays on the LCD.

This system, even though terribly slow(atleast 3 mins for whole process), but completely free.

The project title:
"Free SMS using Landline phone to anywhere in the world"

He completely stole the show: He said, this system can be used anywhere in the world, since you are essentially dialling the destination number and cutting the call.

Also, after the initial handshaking, the destination MCU cuts the ringer of the telephone, so the callee wont be annoyed by the repeated calls.. There were more stories he told.



List of 13 messages in thread
Simple yet stupid      Vignesh Prasad      01/16/06 22:22      
   Simply theft.      Joseph Hebert      01/16/06 22:58      
      oh yes      Vignesh Prasad      01/16/06 23:05      
      two sides of a coin      Jan Waclawek      01/17/06 00:50      
         the way to fight such can be many things      Erik Malund      01/17/06 07:00      
            yep      Jan Waclawek      01/17/06 09:22      
         Exchange      Steve M. Taylor      01/17/06 07:17      
            Same small city      Kai Klaas      01/17/06 07:21      
               City?      Andy Neil      01/17/06 17:21      
            Exchange?      Andy Neil      01/17/06 17:31      
   Complete Rubbish!      Andy Neil      01/17/06 13:28      
      Prototype      Vignesh Prasad      01/18/06 05:36      
   Chapter & Verse      Andy Neil      01/17/06 17:46      

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