Does such a service exist in telephony?

Question

Telephony

When I see a list of recent calls or a contact list on the screen of my mobile phone, I would like to see the status of the subscriber opposite each subscriber, whether his number is busy or not.

Answer 1

How do you imagine it in general?
There is no such thing.

Answer 2

if you have an IP phone, then of course it will be able to do this using standard protocols for these purposes (for example, jabber, xmpp), in traditional telephony it is not always possible to even determine the number, not to mention the status

Answer 3

just like in ICQ - packet request there - packet back with statuses

Answer 4

Very cool feature, would be incredibly handy! Less swearing, less “oh wait, I have a second line”

Answer 5

For the sake of interest, I can ask ours on the switchboard if you kick it in the mail tomorrow.

Answer 6

Within the framework of one, separately taken cellular network (gsm \ 3g), it is technically possible to do this through several cables. But it's better not to.
And the cost of this service will be simply huge, because it will create a huge load if at least some significant number of subscribers appears.
And in IMS networks it is possible, even there are corresponding recommendations 3GPP TS 23.141