+== FE-5680A ==
+
+Pin 1 is Main supply +15 V, drawing about 1.3A reducing to 0.8 A when warmed up.
+
+Pin 2 is Chassis Ground and power supply return.
+
+Pin 3 is a TTL level logic output: High when out of lock, Low when locked.
+
+Pin 4 needs +5 V at about 80 mA to produce any output at all with return to pin 2.
+
+Pin 6 has 1 pps (pulse per second).
+
+Pin 7 is 10 MHz output, with 5 the return for that and maybe any data on
+
+Pin 8 and 9, RS232 is not yet checked.
+