Do indicators and displays work differently when there is more than one line on a phone, or there is a 7914 expansion unit?

The handset light flashes when a call rings on your phone.  A forwarding icon is displayed (phone with and arrow moving to the right) when you forward the prime extension. The following are the extension indicators: Off - Extension available; Steady Green - Extension in use by you; Steady Red - Extension in use by another phone; Flashing Amber - Extension ringing; Flashing Green - Call on hold.