"The dual phone call enables you to receive or to make a call while you're already on the phone.
To activate this service please dial: * 43 # OK
To disable dial # 43 # OK
You can hold in a queue when you want to take or make a further communication.
To put the current call on hold and dial 2 OK
To end the call, dial 1 and OK
To reject the second incoming call and dial 0 OK"