Aastra Telecom SIP 57I - Manual (Page 195)

Global SIP Settings
41-001160-00, Release 2.1, Rev 04 4-71
Configuring Network and Session Initiation Protocol (SIP) Features
Configuring the IP Phones .
Aastra Web UI
Step Action
1 Click on Advanced Settings->Global SIP->RTP Settings.
Global Settings.