Asterisk hold on busy operator?

Question

Asterisk

How to implement the following functionality in Asterisk?
There are two operators (internal number). From the gateway they receive a call to both numbers. If both operators are currently talking, play the notification and leave the caller on the line. When one of the operators is free, then transfer the call to him.
Googled this question. As I understand, there are two options: through queues or the follow me function. I roughly understood the logic like this:
exten => s,1, Dial(SIP\100&SIP\101)
exten => s,2,Backgroung("notification") The
question is, how after playing the notification, leave the call on hold?

Answer 1

You need to implement this with what is called a call queue. Here is the description.
There is also an example:
exten => s,1,Answer
exten => s,2,SetMusicOnHold(default)
exten => s,3,DigitTimeout?,5
exten => s,4,ResponseTimeout,10
exten => s ,5,Background(welcome) - your notification to the caller that operators are busy
exten => s,6,Queue(tech-queue)

Answer 2

without queues

exten => s,1(enter),Dial(SIP/100&SIP/101)
    same => n,Playback(custom/уведомление)
    same => n,MusicOnHold(default,5)
    same => n,Goto(enter)

do it yourself loop protection