Panasonic KX-TD500 Installation Manual page 187

4.2.7 System Option
Value Range
Parameter
(default)
GCOT 1. ON
35
Busyout 2. OFF-RING-
Looprelay GND
3. OFF-RING-
OPEN
4-48 System Programming
When a CO line is busied out manually by the
Manager/ an Operater or automatically by the system,
the state of Loop Relay and Ring-FG are controlled by
this setting.
(3)
Description/Function Reference