*67 15 minutes 512 2000 alaska android asterisk ata bandwidth billing blacklist block blocking buffalo byod call call drop callerid can't receive cancel cancelling cell cisco cisco ata congestion disconnect disconnected domestic ekiga elastix failover fast busy signal fax fee fios forwarding freepbx gateway grandstream gxp how to installation ip321 ip phone latency mobile newbie nokia outage outgoing password pbx plan polycom ip 550 port qos reports retention service settings setup signup sip softphone software spam tcp virtual voipo whitelist