Aastra Telecom 57I CT - Manual (Page 23)

Features in Release 2.1.1
RN-001029-00, Rev 04, Release 2.1.1 19
5i Series IP Phone Release Notes
Configurable Priority Alerting Cadences
The Bellcore cadences on the IP phones for priority alerting are now configurable.
How Priority Alerting Works
When the IP phone detects an incoming call, the phone firmware inspects the
INVITE request in the IP packet for an "Alert-Info" header.
If it contains an "Alert-Info" header, the firmware strips out the URL and keyword
parameter and maps it to the appropriate Bellcore tone.
If there is no keyword parameter in the "Alert-Info" header, or the INVITE
message contains no "Alert-Info" header, then the IP phone firmware uses the
Bellcore standard ring tone.
The ring tone keywords that can display in the "Alert-Info" header are:
Ring Tone Keywords
Bellcore-dr2
Bellcore-dr3
Bellcore-dr4
Bellcore-dr5