There is a problem, there are many phones with 2 lines in each.
You need to make it so that if a person is already talking to someone.
And someone tries to call him, then he would receive the answer “The person is talking on another line, call back later” and either got up to wait or turned off.
How can this be implemented?
I dug up several forums and found nothing working.
Thank you in advance for your help.