Tele

Call Model — DS VT abstracts a backend provider, natively Jitsi.
Concise story of domain space en:smart doorbell.

doorbell metaphor: button controls and tracks video conference call states

Ordinal	Color	State	Visibility	Enabled
-1	White	OFFLINE   No subscriber context or caller device rejected.	Caller	No
0	Cyan	ATTENTION   Subscriber on hook state, like a backlit doorbell, ready to join or originate a call. Double click toggles offhook and single moves to LOOKUP/PAGE.	Subscriber	Yes
1	Blue	LOOKUP/PAGE   If no user or group callee is implicit, clicking prompts for the subscriber or group lookup text, which is then looked up. If the lookup finds an active call, the join processing for this Agent and call begin. If there is an implicit callee, they are rung up. If ring up attempt fails, returns to ATTENTION otherwise moves to IN CALL. Default on hook state for an non-subscribing caller.	Both	Yes
2	Yellow	INCOMING   Indicates incoming events for the agent. Blinks until callee dispatches state. Single click moves the call to a holding state. While in this state information on the call may presented to the callee, indicated by a symbol and retrieved in a popup when the symbol is being displayed, which can include a live feed of the caller. Another single click by callee connects the call. At any time a double click drops the call.	Subscr.	Yes
3	Green	IN CALL   Call active, blinks when additional callers join the call. Single click moves to BUSY. Double click ends call.	Both	Yes
4	Red	AFK/ASIDE/BUSY   A subscriber controlled state indicating the user is in a call and momentarily unavailable.	Caller	Yes
5	Black	DOWN/OFFHOOK/REJECT   Agents may be Callers or Subscribers, both can initiate calls but only a Subscriber can receive them, owns a doorbell. Both start in this state and may enter it as a result of network events. Clicking if enabled moves to ATTENTION or OFFLINE depending on entering state and network.	Both	Subscr.