Compared to connecting phones directly to the public telephone network this allows you to use a lot of additional features:
Call Answering
Ring Groups
Call Pickup
Call Forwarding
Call Forking
Voicemail as Email
Time-Based Routing
Privacy Manager Call Management
Local Dialplan
Status Panel
Call Monitor
Transfers
Call Parking
Music on hold
Conferences
With Selected Phones
Busy Lamp Field
Intercom
Simultaneous Outbound Other
Callthru
Answer SIP Calls to account-name@pbxes.org
Integration
Looks like call thru is part of the basic system.
Callback for example is only available for paid account and only 3 callbacknumber per acount.
