Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
???
06/17/05 18:00
Read: times


 
#95203 - tricky
Responding to: ???'s previous message
Mehdi said:
When you press key #9 ,a small sound (click that andy said) can be heard in B_party's phone set

Actually, 9 clicks.

you need to amplifying this click

It's not just a question of amplifying it - you also need to distinguish this click from any other sound on the line.
That's the hard part!

DTMF is specifically designed to be easily distinguished from normal speech on a telephone line.

Maximum amplitude of this click is less than 0.8 volt

Trouble is, the telephone system gives you no guarantee as to how these pulses will appear at the B-Party's set - if they appear at all!.

Again, DTMF is specifically designed for transmission through the analogue telephone system.

List of 16 messages in thread
TopicAuthorDate
Pulse Detection            01/01/70 00:00      
   Discussed here            01/01/70 00:00      
      I'll check it            01/01/70 00:00      
         Detect where?            01/01/70 00:00      
         pulse detection            01/01/70 00:00      
            I doubt it.            01/01/70 00:00      
               Re: I doubt it            01/01/70 00:00      
         Unlikely to work            01/01/70 00:00      
      First MicroController Project            01/01/70 00:00      
         Look over here,,,,            01/01/70 00:00      
            Cliche            01/01/70 00:00      
   But if there is no way...            01/01/70 00:00      
      tricky            01/01/70 00:00      
         Last Speech!            01/01/70 00:00      
      Thanks            01/01/70 00:00      
   Thanks            01/01/70 00:00      

Back to Subject List