Yesterday, I configured the office phone system to forward calls to an outside number. No big deal, right? Phone switches have been doing this for ages.
After I set up the menus properly, I watched the logfiles as I tested things out. My call came in on an IAX trunk and reached the menu, where a keypress sent it on its way to the external number, again on an IAX trunk.
Here’s where things get interesting! As I watched in wonder, Asterisk realized “Oh! This is a conversation between two external parties. What am I doing here?” It then negotiated for both parties to speak directly to each other, seamlessly handed the call off and dropped out of the loop.
This is truly amazing stuff. Hundred-thousand-dollar phone switches don’t do this. Ordinarily, two trunks would have been tied up for this call, adding expense and degrading sound quality while they were in use.
Voice over IP protocols completely change the nature of telephony.