HYBREX DK3-21 - LED Indicators; CO Key LED Status; SPK Key LED Status; Signalling Tones

LED Indication
 CO key (Trunk Line)
Idle (Steady Off)
I-Use (Steadily On ) Green
Busy (Steadily On) Red
Ring (Fast Blinking) Red
I-Hold (Fast Flashing) Green
System Hold (Fast Flashing) Red
Exclusive Hold (Slow Flashing) Green
 SPK key
Idle (Steady Off)
I-Use (Steadily On ) Red
Save Redial (Fast Blinking) Red
System Program (Fast Flashing) Red
Call Forward (Fast Flashing) Red
Signalling
 Tone
Dial Tone
Ring Back tone
Busy Tone
Override Tone
 Ring
Intercom
Trunk
Hold Recall