For SIP endpoints that are attached to a DPMA-configured Digium phone, the subscribe_to parameter should point to a special hint automatically created by DPMA. This hint is in the format "auto_hint_<peer>," e.g.:
In this case, it is not necessary to create a dialplan hint, as it is automatically created by DPMA.
For non-DPMA-configured endpoints, no "auto_hint" is created, and subscriptions should be a normal SIP URI that is provided by the target system, e.g..:
or, simply to an extension, where the phone will automatically subscribe to the registered server, e.g.:
Also, when DPMA is not used, it is necessary to create a dialplan hint, e.g.:
Users of DPMA with older versions of Asterisk, or chan_sip instead of chan_pjsip, should note that the callcounter sip.conf parameter is necessary.