It is necessary that there be a call waiting mode if all 4 GSM numbers of the online store are busy. Where to google?

Question

Telephony

So that when a person calls, they say to him "Wait, you will be answered soon." Orient, please, what is the name of the scheme of the device or service? Where to google? Thanks

Answer 1

auto attendant

Answer 2

in general - asterisk.

Answer 3

This is a mobile call center service.
moskva.beeline.ru/business/products-and-solutions/...