I think the congestion tone here is basically the Call Progress Tone. Rather than actually telling you that the system is tied up it will just make you wait until it puts the call through. I've come across it when there's been a network glitch or some sort. E.g. one weekend two of eircom's major switching centres had a software glitch (they'd centrally uploaded the wrong software to the network! [or one of their "switching partners" did] and calls were being handled by other switches which all started to run slow as they were obviously under heavy pressure. So lots of "bebebebebe" before you were connected. The system seemed to accept call attempts just made people wait until it was good and ready to complete them.
----
Also on the being dumped off the system if you don't dial with in X time we've a weird siutation here:
1) on a normal line you'll get a dial tone, then after about 50 seconds an engaged tone, designed to cause any automated equipment to hang up. After a further 50 seconds the line goes silent for 30 seconds then the DC feed is cut.. you'll hear a relay cutting the power and then complete silence until the phone's replaced.
2) if the line has voicemail: (as 70% do)
you pick up.. dialtone for 35 seconds after this period you'll be prompted like this "mailbox name" please enter your password. (Voicemail can also be accessed by dialling 171)
3) If there's DSL on the line the line card is programmed not to cut the power to the line even if it's left off-hook so it will provide a dial tone as normal then just go to a never ending busy tone if you don't hang up.
-----
The old crossbar lines behaved very similarly. Dialtone (50 seconds) busy tone (1 min) then cut the line off until it is reset by replacing the reciever.
[This message has been edited by djk (edited 10-17-2003).]
