AASTRA 4225 for MX-ONE Telephony Switch - Manual (Page 13)

13 Dialog 4223 Professional/Dialog 4225 Vision
Description
Lamp indications
Ô
Extinguished lamp The feature is not active.
Х Ф
Steady light
The feature is active or the multiple
represented line is busy.
Ц Ф
Slowly flashing lamp The line (or feature) is put on hold.
Ц Ф
Rapidly flashing lamp An incoming call.
Х Ф
Light with short breaks Ongoing call.