Does the call to grandstream ht503 end incorrectly?

Question

Asterisk

When there is a call from a mobile phone to a home phone through the grandstream ht503 gateway and if you want to end the call on the handset, it does not end correctly. The call for some reason goes further, what could it be?

Answer 1

For starters, it should be something like this...
exten => _X.,1,Dial(SIP/${EXTEN}@ht503,20)
Or like this:
exten => _X.,1,Dial(SIP/ht503/ ${EXTEN},20)

Answer 2

From a meager description, let's assume that the call is according to the scheme:
cellular => GTS => FXO => Asterisk => FXS => device
You end the call on the "cellular" side, but the call does not end.
Short beeps are heard in the analog tube, but astrisk counts the seconds further.
If so, then you need to configure clear signal detection on the gateway's FXO port.
To do this, write down these signals with an asterisk. In the sound editor you analyze their main frequencies, duration and duration of silence.
You fill in the received data according to the manual to the gateway.