Why is happening this?

Hello, when i get and incoming call, and the IVR answer then the client press 1 the SIP/201 ring but if the client hangup the line keep ringing for at least 10 seconds then i see busytones in the channel
I saw all this using the dahdi_monitor tool!

Me question is; Why it keep sending data to the analog phone card?
Yes i have disconnect supervision, but i still having the problem!

When the client hangup the RX stop to sending data but the TX still sending data. How to fix that?
Yes i hangup handguponpolarityswitch and answeronpolarityswitch set to yes

Because your service provider isn’t providing disconnect supervision (probably quite a common limitation for domestic lines), or because you haven’t told dahdi the correct type of disconnect supervision to look for).