Aastra Telecom SIP 57I - Manual (Page 267)

Operational Features
41-001160-00, Release 2.1, Rev 04 5-57
Configuring Operational Features
Operational IP Phone Features
Aastra Web UI
1 Click on Basic Settings->Preferences->General.
2 The "UPnP Mapping Lines" field is set to 0 by default. If required, change the setting to a specific
line by selecting a line from the list. Valid values are 0 through 10. The line you select is the line that
your remote phone uses to perform Universal Plug and Play on the network you are connecting to.
3 Click to save your changes.