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For DPMA, this functionality is controlled by the "send_to_vm" phone configuration option in res_digium_phone.conf. This option is enabled by default by DPMA. It is disabled by default for phones provisioned manually. To enable manually-provisioned phones to use this functionality, the send_to_vmail keymap must be enabled. Further, the Send and Transfer capability require the use of Asterisk 11 or greater - or "-digiumphones" branches of older versions - due to the DIVERSION header support requirement.
Incoming Calls
On an incoming call, Sangoma phones present four softkeys to the user:
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When the Send VM softkey is pressed, the phone sends a DIVERSION header to Asterisk that contains a REDIRECTING reason "send_to_vm."
Dialplan example
The following presents a dialplan example of using the DIVERSION header and the X-Digium-Call-Feature header to handle Send to VM, Transfer to VM, and Direct VM dial.
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