There is no slate on A. The schematic shows that the ringer coil should have 4 wires, but in reality, it's only 2, just red and black, no slate or slate red..

But, I tried putting red to L2, and black to F.. When plugged into the jack, I got a single "goonnnnng". Picked up the handset, had a dialtone, and a single "cling" from the phone. Put the handset back on hook, and "gonnnnng". Interesting..

Call the phone from my cell, BUSY signal. Huh?