Trunks
"Trunk" refers to another server/PBX that can be connected to the MOR system.
When calling such a device, we send the full number which was dialed before.
For example, when dialing a simple device, we would use:
Dial(SIP/some_device)
If this device is a Trunk, we use:
Dial(SIP/some_device/${EXTEN}).
This lets Trunk decide to which device (connected to the Trunk) to route the call.
If you want to make a device Trunk, just mark it as Trunk in the device details: 
No/Yes/Yes with ANI.
Trunk with ANI
It is sometimes necessary not to bill a whole trunk as one client, but to to bill separate clients connected to the server/pbx (trunk) separately.
In order to do this, you should mark a device as Trunk with ANI.
Now, when a device connected to the Trunk dials through MOR, MOR checks the calling device's CallerID. If the CallerID is present for some device in the MOR, MOR recognizes this device as a valid device on the MOR and assigns the call to it instead of to Trunk.
