A consideration in the voice policies is to review the existing or planned PSTN call capacity in each site and make sure it will support the simultaneous ring feature. This is a very popular feature with users because it enables them to answer calls on Lync endpoints or a mobile phone, but it consumes an extra PSTN trunk for each call. In a scenario in which a PSTN caller dials Alice at Company ABC, that call consumes one trunk, and the simultaneous ring to Alice’s mobile phone consumes a second. If Alice answers the call on her mobile phone, both trunks are still in use for the duration of the call.