Client(some organization) can have extensions with type='phone'. Theese extensions are:
Some device (phone/softphone etc) that can receive incoming call and do outgoing calls (SIP account in ohter words)
(optional) Emploee who assigned to this extension
For example here is 3 extension: 101,102,103 have SIP account and assigned empolee, 104 is just a SIP account:
Also client cn ha ads