Hi Wakar,

You persist in asking the same question without acknowledging the suggestions that have been given to you. You keep trying to build a high-rise building without working on the foundation first.

You say your hardware is designed and works. How do you know? If you don't know how the software will work, your hardware ISN'T finished.

You're concerned with how to detect pulses. OK, but have you considered how you are going to detect pulses when two or more users start dialing SIMULTANEOUSLY? Which they will, sooner or later. Will your hardware support this? Will your uC have sufficient horsepower to perform its chores in the time it needs to, given the number of simultaneous users.

In other words, without knowing how your software is going to work, you *really* cannot know if your hardware is even capable of handling the task.

A typical design involves identifying the algorithms used by the software, doing some initial design of the hardware, then a series of hardware/software design compromises and iterations. Hardware that's finished before the software is planned out is a disaster waiting to happen.

You're using DTMF phones. Unless they are the old variety with a switchable pulse/DTMF output, you have to deal with DTMF. Why are you using pulse dialing at all? A DTMF decoder chip will simplify the software, but of course with the hardware all finished (and correct!) I suppose that's out of the question.

Have you considered maintenance? How to update the software once the product is installed? These should be considered at the initial design stage so you don't inadvertently "paint yourself into a corner."

Lots of things to think about, stop worrying about snippets of code, and start designing.

Dennis