??? 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. |
Topic | Author | Date |
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 |