Polycom SIP 3.1 - Manual (Page 288)

Administrator’s Guide SoundPoint IP / SoundStation IP
B - 6
Response Support
The following SIP responses are supported:
1xx Responses - Provisional
2xx Responses - Success
Subject No
Subscription-State Yes
Supported Yes
Timestamp No
To Yes
Unsupported No
User-Agent Yes
Via Yes
Warning Yes Only warning codes 300 to 399
WWW-Authenticate Yes
Header Supported Notes
Note In the following table, a “Yes” in the Supported column means the header is sent
and properly parsed. The phone may not actually generate the response.
Response Supported Notes
100 Trying Yes
180 Ringing Yes
181 Call Is Being Forwarded No
182 Queued No
183 Session Progress Yes
Response Supported Notes
200 OK Yes
202 Accepted Yes In REFER transfer.