I think the lag on turn off is going to cause a false hold condition. Wish I had a 1A2 set up to play with. Put a buttset, turned on, on the 400 card output for line 1, white blue pair, temporarily short the A control white orange pair to light the lamp. Then remove the short across the white orange pair and I'll bet the line card will go on a false hold. Opening A lead before the talk pair is opened does that. Turning the lamp on slightly before or after T and R close, is insignificant in the real world. But, when you hang up the phone, the A lead has to open first, or within a few microseconds of T and R opening. John C.
