Panasonic KX-TD500 System Reference Manual page 454

6.00 Automatic Callback
6.01 Automatic Callback-Trunk
Description
When calling an outside party and an idle line is
not available, the extension will be called back
when the CO line becomes available. The
extension can seize a CO line only by off-
hooking.
We call this function "Callback-Trunk". "Callback-
Trunk" has 2 types.
1. When seizing a CO line, it checks whether a
CO line is idle or not. If no line is available, a
busy tone is sent. Once a CO line is available,
the extension will be called back.
(If the telephone goes off-hook before the
callback is received, callback is cancelled and
you will hear a dial tone.)
2. After receiving all dials of the outside calls, it
checks whether an idle CO line is available or
not. If there is no idle line, you will hear a busy
tone. As soon as a CO line becomes idle, it
will be seized. Once the extension is off-hook,
the last number dialed is sent and you will
hear the CO line ring.
Type 1 is the default.
Each type can be set to a trunk group by the
dumb command "CAI". This function can activate
extensions that are set to "Yes" in the "Automatic
callback-Trunk" of Station (1/4).
Programming
System Programming
"Extension-Station (1/4)",
Automatic Callback-Trunk
"CO Access Instantly"
Conditions
If the telephone is off-hook before callback
ringing starts, this feature is cancelled.
A maximum of 64 extensions are able to callback
at the same time.
The following features can also be accessed:
• Local CO line Access
• Trunk Group 01-48 Access
• Calling by CO button (Private CO, Single
CO, Group CO) in the hands-free mode.
4-C-20
Reference
VT Dumb
10-G-1.01 11-C-24.00
11-C-47.00