Firstly great work with the site, I've updated the settings on my Obi110 to match the ones you recommend here, unfortunately it caused me a few issues, Setting CPCTimeThreshold to 0.09 on an Obi110 results in a value of 0 being used on reboot meaning incoming calls would get dropped after a second (I'd previously set this to 90 and it worked fine) and now I can't use # to bypass Asterisk whereas I could before as entering numbers just gets ignored the line then gets dropped (you can hear the clink-click sound) and then the Asterisk dial tone takes over.
I've since set the CPCTimeThreshold to 90 and all is fine again apart from the above bypass issue (which might be my fault due to RX changes ~ see below).
Also I've never heard that howling tone used before, is it custom?
--- Below is slightly off topic but maybe you might be able to help (feel free to separate this into another thread).
We have a bog standard Motorola DECT phone connected to the obi which works generally fine but the volume seems to fluctuate during a call, e.g. When you talk the volume of the caller gets reduced making them hard to hear. I've set the ChannelRxGain on the phone port to -5 and RX to 8 on the Line which has helped somewhat but it's still not great.
If you have any suggestions they'd be greatly received :D