Call progress means many things:
Dial Tone detection
Ringing tone and various cadences of these
Busy – fast and slow busy
Called party answered – which in some phone company means a reversal of loop current
Called party hung up - which in some phone company means another reversal of loop current
Error tones- the bee-bee-bah you sometimes hear
Timeouts
Incoming ring (high voltage 20Hz
So it depends on what progress you want to detect.
It a’int easy which is why people buy $5 chips to do this.
From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf Of Farzlina Ab.Hadi
Sent: Tuesday, May 03, 2005 11:27
PM
To: AVR-Chat@yahoogroups.com
Subject: [AVR-Chat] call progress
detection
hello..do you guys think that my approach for call progress detection by sampling (using a port as input) at certain intervals (using timers) is wise? is there any other way of doing it?
thanks!
elin