[asterisk-users] No intercom splash tone?

[Ken Morley]

Environment:
Asterisk 1.2.14, FreePBX 2.2.0, Aastra 480i IP telephones firmware
version 1.4.1.1077.

Problem:
Intercom feature: the dialed phone does not play the splash tone when
auto-answering an intercom call.  Otherwise, intercom works perfectly.

Questions:
What is the extensions.conf syntax to trigger a splash tone in Asterisk
1.2.14 (from the documentation and posts I've found, it has changed as
Asterisk has evolved)?

What SIP header, etc. does the Aastra 480i firmware 1.4.1.1077 need to
play a splash tone?

What is the suggested methodology for further troubleshooting?

Many thanks!

Ken Morley