Everything's fine with the schematic. Obviously, this circuit is used for a synchronization purpose. Pin5 should be connected to +5V (or the positive rail) by a pull-up resistor. The "60Hz" labeled rail, in this case should be considered as an output rail. On that same rail, if observed with scope, the signal should be rectangular with F=60Hz, period ~16,67ms(for 60Hz mains), and Duty_cycle= ~50%. The "60Hz"-rail is probably connected to the microcontroller, which is using the signal for synchronizing with the mains voltage and is commonly used for switching or phase regulating of AC loads with triacs.