Ah, the good old days of CCM 3.3 and before. /sarcasm ;)
I would only add that the doc linked is for these older versions of CCM. The concept is the same for 4.0 and forward but you have to set the max calls for the DN to 2 and the busy trigger to 1 for the call forwarding to the second and subsequent lines to work. In versions before 4.0 the 2/1 setting was implied because that was the limitation of the system.
Be careful with this setting because it has to be set on every line that uses a number. If you have shared lines for a DN and you set 2/1 on one phone but leave it at the default of 4/2 on another phone the call forwarding will not work as you want it.
I also believe with the older phones (7940/7960) you might have issues with the second and third (and so on) lines not really showing when they ring (other than the jingling phone icon on the far right by the line button) because the caller ID display will cover the whole LCD screen versus the 2 line boxes that show up for caller ID on the newer phones. You might want to check this one out because I don't have a phone in front of me right now to test.
Lessons re-learned after I just finished making a UCM 6.1(2) system match the config from the original CCM 3.3 system that was originally implemented to look like the Nortel that it replaced.
