This is mostly correct. But you have to be aware of the difference between Multiple Call Ring (MCR) and Single Call Ring (SCR):
MCR: Multiple Call Ring tells the system to allow as many new phone calls as you have phones programmed with that DN. In other words, if you have 5 phones with "key 2 MCR 5000" then you are allowing 5 calls to terminate on DN 5000. As each new call is picked up only the light for the phone that picked up the call remains lit. On all of the other phones, the lights stop flashing when the call is answered and are then ready for a new call.
SCR: Single Call Ring tells the system to allow only one call on this DN. You can have 5 phones with "key 2 SCR 5000". This says that only one call can come into DN 5000. All phones ring and when it is picked up by any phone, the lights on all of the remaining phones remain lit and no other calls can terminate on 5000. Call redirection programming would then take place if programmed.
Hope this helps,
cagey1560