Camden CM-1290-7224 Stainless Steel Flush Mount Single Gang Key Switch Control, DPDT Maintained, Red and Green 24V LEDs

The switch takes any mortise cylinder in the 1 inch to 1-1/4 inch range along with its cam. The 1-1/8 inch mortise cylinder is the common pairing and sits in the middle of that range. Match the keyway to whatever the rest of the building uses so the switch works on the existing master key system.

Maintained means the switch stays in the position you turn it to until someone turns the key back, rather than springing back on release. That is what you want for hold-open, night latch, or arming and disarming a door, where the state has to persist. Momentary is the choice for a single release or unlock pulse. DPDT gives you two independent sets of transfer contacts, so one set can drive the door device while the second reports the state back to an access control panel or alarm.

Red and green LEDs rated at 24V. Run them off a 24V supply, not 12V, or they will not indicate correctly. The two colors give you a visible state at the door, which pairs with the maintained action: green for released or held open, red for secure, depending on how you wire it.

The switch mounting bracket comes pre-assembled, so you are not building it up on site. It is hardwired, with no wireless option, so you need a cable run from the switch back to the door controller, power supply, or panel. Plan the run for the 24V LED feed as well as the two switched circuits.

That is exactly what a mortise key switch is for. The DPDT maintained contacts are dry transfer contacts that you wire into whatever device controls the opening, so it can break power to a maglock, signal an operator, or shunt an alarm. The switch itself is the control point, not the locking device, so the mag lock, strike, or operator is a separate purchase, as is the mortise cylinder.

Yes, it is a commercial grade device with a stainless steel faceplate, which is why it holds up in corridors, stairwells, and exterior vestibules where a painted plate would scuff. Property managers standardizing across a building can use the same switch at every opening and key all the cylinders alike.