Polycom Version 1.4.x 17 - Manual (Page 71)

Administrator Guide - SoundPoint ® IP / SoundStation ® IP Optimization
Copyright © 2004 Polycom, Inc. 63
4.5.3 RTCP Support
The phone supports RTCP per RFC 1889. For each RTP stream, which, by conven-
tion, uses even ports only, the next higher odd port is used to send and receive RTCP
reports.