In the event that a call is transferred to a destination extension that is busy, or unanswered, the ringback mechanism will send the call back to the transferring party, with a modification to the CID. The new CID presented to the transferring party will be prefixed by “Ret:” to indicate that the call is returning, as well as a the extension number of the destination extension to which the original call was transferred. The Ringback caller id will have the form :
“Ret: [original intended destination extension]CID”
Note that Ringback functionality is only activated on destination extensions with follow me or voicemail enabled. Transferred calls to extensions with neither configured will ring indefinitely if unanswered, or fail with an engaged tone should the extension be unavailable.
Note that the follow me of the destination extension will be evoked before the ringback occurs, so a transfer to an extension with follow me enabled, will only ring back to the intermediary extension if the destination extension and all extensions in its follow me list, are unavailable or unanswered.
If the ringback mechanism sends the call back to the transferring extension and this extension is no longer available, or the call is unanswered, the destination will be as in the table below:
|
Intermediary Voicemail Enabled |
Intermediary Follow me Enabled |
Destination Voicemail Enabled |
Destination Follow me Enabled |
Ringback Occurs |
Ringback Failover Destination |
|
N/A |
|||||
|
√ |
√ |
Destination extension Follow me failover |
|||
|
√ |
√ |
Destination extension voicemail |
|||
|
√ |
√ |
√ |
Destination extension Follow me failover. |
||
|
√ |
N/A |
||||
|
√ |
√ |
√ |
Destination extension Follow me failover. |
||
|
√ |
√ |
√ |
Destination extension voicemail |
||
|
√ |
√ |
√ |
√ |
Destination extension Follow me failover. |
|
|
√ |
N/A |
||||
|
√ |
√ |
√ |
Destination extension Follow me failover. |
||
|
√ |
|
√ |
|
√ |
Destination extension voicemail |
|
√ |
√ |
√ |
√ |
Destination extension Follow me failover. |
|
|
√ |
√ |
N/A |
|||
|
√ |
√ |
√ |
√ |
Destination extension Follow me failover. |
|
|
√ |
√ |
√ |
√ |
Destination extension voicemail |
|
|
√ |
√ |
√ |
√ |
√ |
Destination extension Follow me failover. |
|
Intermediary Voicemail Enabled |
Intermediary Follow me Enabled |
Destination Voicemail Enabled |
Destination Follow me Enabled |
Ringback Occurs |
Destination After Ringback |
|
√ |
|
√ |
|
√ |
Destination extension voicemail |
|
√ |
√ |
√ |
√ |
Destination extension Follow me failover. |
|
|
√ |
√ |
N/A |
|||
|
√ |
√ |
√ |
√ |
Destination extension Follow me failover. |
|
|
√ |
√ |
√ |
√ |
Destination extension voicemail |
|
|
√ |
√ |
√ |
√ |
√ |
Destination extension Follow me failover. |
Table 25: Ring-back behavior
|
Note: Users need to be informed as to what to expect. With ring-back enabled their phones should ‘ring by itself’ once available. If the hand-set it picked up, they should hear ringing while the initial calling party is being contacted. If the other party is now on the phone and also has neither follow-me nor voicemail enabled, when the handset of the phone on which ring-back was initiated is picked up, the user would hear a busy tone. A second round of ring-back will then be initiated. I.e. once the original caller (now on the phone) ends the call, his phone will ring, and picking it up, the initial called user would be attempted again. |