Panasonic KX-TD500 System Reference Manual page 236

(3) Music on Hold is sent to the caller in the
queue until a group member answers it.
(Example)
In the following case, Music on Hold is sent to
the caller, during 4T (60 seconds) interval.
→ 4T
O1W
Sends Music on Hold
3-D-18
Timetable operation examples
(Example 1) O1S → 4T → 2T → O2S → TR
(1)
UCD Group
(1) The caller hears OGM1, if available.
(Example)
Sorry, all lines are busy.
Please wait a moment
If OGM1 is busy or Out of Service, this
step will be skipped. Then the caller
hears the ringback tone.
(2) The caller hears Music on Hold for
90 seconds (4T + 2T).
(3) The caller hears OGM2.
(Example)
Sorry, all lines are still busy.
Calling the Operator.
(4) The caller is transferred to the
Overflow destination (Operator or
covering extension).
Note:
• During steps (1) through (3), the
caller will be connected to a UCD
group member as soon as
anyone of members becomes
available to answer the call.
(2) (3) (4)