Panasonic KX-TD500 System Reference Manual page 527

6.02 Unattended Conference-Two
Appearances
Description
When an extension is in a Conference-Two
Appearances with two outside parties, the
extension can leave the conference and
establishes the CO-to-CO call between other two
parties by pressing the CONF button: this is
called Unattended Conference Two
Appearances.
During an unattended conference between the
two outside parties, the indicators on both buttons
(both are DNs, or one is DN and the other is CO,
or both are COs) flash in 120 wink.
To execute this function, assign "System-Class of
Service", CO Transfer Mode to "Yes".
The duration of the Unattended Conference is
restricted by "Group-Trunk Group", CO-CO
Duration Limit.
Programming
System Programming
"System-Class of Service (1/3)",
CO Transfer Mode
"Group-Trunk Group (1/3)",
CO-CO Duration Limit
Reference
VT Dumb
10-D-4.01 11-C-7.00
10-E-1.01 11-C-15.00
4-G-11
Conditions
If the extension is not allowed to execute this
function in Class of Service, or either or both of
the other parties are not outside ones, pressing
the CONF button is ignored.
When the two occupied CO lines belong to
different trunk groups, the following time limits
apply to each case:
If one party is an outgoing CO call and the
other is an incoming CO call; The duration
limit follows the trunk group of the incoming
CO call.
If both are outgoing CO calls or both are
incoming CO calls; The longest duration
limit assigned to one of the two trunks is
used.
Unattended Conference Recall starts 50 seconds
before the time limit.
30 seconds of no answer after the start of the
Unattended Conference Recall causes Intercept
Routing-No Answer.
For the further detail, refer to Section 3-F-5.00
"Intercept Routing-No Answer (IRNA)".
Alarm tone is sent to both outside parties 15
seconds before the time limit. When CO-CO
Duration Limit applied is expired, both outside
parties are disconnected.