CiscoSPA8800, PSTN State: Ringing?

Question

VoIP

I'm trying to set up a connection LG GDK-162 FXS ---- FXO Cisco SPA8800
in Cisco in the line status writes PSTN State: Ringing
, respectively, the line is busy, the call does not go
through the voltage on this line is 32V,
that is, the line is not released
if I pull out the cable status: idle
tried to configure Disconnect Tone
recorded beeps turned out
[email protected],[email protected];3(.25/.25/1+2)
does not help.
I set up 3 lines at the same time, the situation is the same for all.
sometimes the line hangs up and the call goes through.
where to dig?
Will the Icon BTD8 rebound detector help?