DS-KH9510-WTE1 call drops immediately after pressing unlock

[Hyperway]

I have an issue with my DS-KH9510-WTE1 (B), which is connected to a DS-KV8113-WME1. When there is an incoming call and I answer it, as soon as the unlock button is pressed, the call ends. Have I missed a setting somewhere?

 

[JB1970]

I have an issue with my DS-KH9510-WTE1 (B), which is connected to a DS-KV8113-WME1. When there is an incoming call and I answer it, as soon as the unlock button is pressed, the call ends. Have I missed a setting somewhere?

I think that's the norm. You identify the caller, press the unlock button to release the door/gate and terminate the call. I don't recall an option to keep the connection open until terminated manually.