McDewey

Endpoint Returns 486 Busy You can configure all lines on a Unified CM with a “busy trigger.” After the number of active calls to that line reaches the busy trigger, Unified CM will prevent further calls from being presented to that phone by initiating a call forward busy without sending another INVITE to the phone. However, due to misconfiguration or the potential for calls of which Unified CM is not aware to exist on the phone (for example, a phone in a dialing state that has not yet sent an INVITE), the phone may need to manage its own busy trigger and autonomously throttle calls. Phones accomplish this by sending a 486 response code to an INVITE. Although Unified CM may have Call Forward Busy behavior configured for a line (for example, forward to DN or forward to a voice-messaging system), that behavior does not get exercised when a 486 message is received from the phone. Instead, the 486 message will be passed back to the original called party. Announcements for Certain Call Setup Failures When Party A calls Party B, there are circumstances in which the call cannot complete and an announcement as to the reason for the call failure is played to party A. A simple example is when party A misdials the B’s number and the misdialed number does not exist. This results in a vacant code error. In this same scenario if Party A were an SCCP phone, then party A would be connected to an annunciator and would receive an announcement similar to “Your call cannot be completed as dialed. Please consult your directory and call again or ask your operator for assistance. This is a recording.” Once the announcement is completed, the Party A would hear the re-order tone if they were still offhook. Previous to Unified CM Release 8.0 if Party A were SIP, they would immediately hear re-order locally on the phone as a result of the 4xx SIP error message and not hear the announcement-Unified CM 8.0, SIP phones now have parity for error scenarios where an announcement is performed (for example, vacant code). The call flow for these announcements utilizes standard SIP. A sample of the flow is shown after this. In this scenario, the announcement is played and the 4xx/5xx error code is sent as before. The SIP 183 contains SDP. Figure 1: Annunciator Insertion Call Setup Scenario SIP Line Messaging Guide (Standard Edition) for Cisco Unified Communications Manager 32 SIP Standard Line Interface Endpoint Returns 486 Busy