Polycom CX5500 Administrator's Guide

Polycom CX5500 Unified Conference Station Administrator’s Guide 1.1.0
Polycom, Inc. 356
6xx Responses - Global Failure
Supported 6xx SIP Responses
Response
Supported
600 Busy Everywhere
No
603 Decline
Yes
604 Does Not Exist Anywhere
No
606 Not Acceptable
No
Hold Implementation
The phone supports two currently accepted means of signaling hold.
The first method, no longer recommended due in part to the RTCP problems associated with it, is to set
the “c” destination addresses for the media streams in the SDP to zero, for example, c=0.0.0.0.
The second, and preferred, method is to signal the media directions with the “a” SDP media attributes
sendonly, recvonly, inactive, or sendrecv. The hold signaling method used by the phone is configurable
(see SIP), but both methods are supported when signaled by the remote endpoint
Note: Hold Methods
Even if the phone is set to use c=0.0.0.0, it will not do so if it gets any sendrecv, sendonly, or
inactive from the server. These flags will cause it to revert to the other hold method.
Reliability of Provisional Responses
The phone fully supports RFC 3262 - Reliability of Provisional Responses.
Transfer
The phone supports transfer using the REFER method specified in draft-ietf-sip-cc-transfer-05 and RFC
3515.
Third Party Call Control
The phone supports the delayed media negotiations (INVITE without SDP) associated with third-party
call-control applications.

Polycom CX5500 Specifications

General

Brand	Polycom
Model	CX5500
Category	Conference System
Language	English