Union Switch & Signal 514 code used a shunt line circuit. (very similar to 506)
514 was capable of 35 field locations with a minimum of 7 controls and 7 indications at each
station, but could be expanded to add more control and indication steps with extension units,
which added 8 steps, or 7 functions, per code cycle.
514, as with 506, used KP Magnetic Stick relays for progressive control delivery.
Office Code Unit
Field Code Unit
Field Extension Unit
KP Line & Staring Relays
The rear of a large machine
showing the office storage units,
which store the indications from
the field locations.
