Problem to hangup - Analog TDM2400P - PBX Harris 20-20

I have a TDM2400P board connected to a HARRIS 20-20 control panel.
When a call from HARRIS is detected by the DAHDI, if the user cuts the call, the DAHDI does not detect the cut.

Attached the chan_dahdi.conf

[general]
immediate=yes

[trunkgroups]

[channels]
context=from-pstn
signalling=fxs_ks
rxwink=300 ; Atlas seems to use long (250ms) winks
usecallerid=yes
hidecallerid=no
callwaiting=yes
usecallingpres=yes
callwaitingcallerid=yes
threewaycalling=yes
transfer=yes
canpark=yes
cancallforward=yes
callreturn=yes
echocancel=yes
echocancelwhenbridged=no
faxdetect=incoming
echotraining=800
rxgain=4.0
txgain=4.0
callgroup=1
pickupgroup=1

;Uncomment these lines if you have problems with the disconection of your analog lines
;busydetect=yes
;busycount=4
;answeronpolarityswitch=yes
;hanguponpolarityswitch=no

;busydetect=yes
;busycount=3
;callprogress=no

;immediate=no
immediate=yes

#include dahdi-channels.conf
#include chan_dahdi_additional.conf

I was reading and trying but I can not get it to work.
Thank.

How are you expecting it to detect it.

Is it FXO or FXS.

If FXO, does it remove battery on disconnect or does it send a tone on disconnect?