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REX & Door Contacts

Each door on the AccessCore One controller has a dedicated 3-pin input port for its Request-to-Exit (REX) device and its door position sensor (DPS). This page covers wiring both inputs.

These inputs are what let the controller release a door for egress from the inside and know whether a door is open or closed. Without them, the controller can still unlock a door on a valid credential, but it cannot detect a forced door, a held-open door, or an inside exit.

See the Terminal & Connector Reference for the full board map, and Wiring Locks for how a REX event releases the lock relay.

The door input port​

There are four door input ports along the left edge of the board, one per door, each sitting directly beside that door's reader port. Each port is a 3-pin connector.

PortSilkscreen labelDoor
J5DOOR 1Door 1
J6DOOR 2Door 2
J7DOOR 3Door 3
J8DOOR 4Door 4

Pin order on every door input port, top to bottom as printed on the silkscreen:

Wiring REX and a door contact to the 3-pin input port — RXn, Sn, GND

PinSilkscreenFunctionWire to
1RXnRequest-to-Exit (REX) inputOne side of the REX dry contact
2SnDoor position sensor (DPS) inputOne side of the door contact
3GNDCommon ground / return for both inputsOther side of both contacts

Both RXn and Sn are optically isolated dry-contact inputs. You wire a dry (voltage-free) contact between the input pin and the GND pin on the same port. The single GND pin is the common return for both the REX and the sensor on that door.

On the board the n is the literal door number: the silkscreen prints RX1/S1/GND on J5, RX2/S2/GND on J6, RX3/S3/GND on J7, and RX4/S4/GND on J8. This page uses RXn/Sn as shorthand for whichever door you are wiring.

:::danger Dry contacts only — never apply external voltage The RXn and Sn pins are dry-contact inputs. Do not apply any external voltage (no 12 V, no 24 V, no panel output power) to these pins. Back-feeding voltage into an input can damage the optical isolator. Connect only a voltage-free switch, relay contact, or open-collector/dry output between the input pin and GND. :::

:::note Keep each door's ports together Each door's input port sits next to that door's reader port (J14/J15/J16/J17). Land Door 1's REX, sensor, reader, and lock all on the Door 1 group. Crossing a sensor from one door onto another door's port will report the wrong door's state. :::

Request-to-Exit (REX) on RXn​

The REX input releases the door from the inside so a person can exit without presenting a credential. A REX event:

  • Unlocks the door (releases that door's lock relay) for egress.
  • Suppresses the forced-door and held-open alarms while someone exits normally, so a legitimate inside exit is not flagged as a break-in.

Typical REX devices​

  • PIR motion REX — a request-to-exit motion sensor mounted over the door on the secure side; provides a dry relay output that closes on motion.
  • Push-to-exit button — a momentary or maintained dry-contact button.
  • REX output from an exit device — the dry-contact REX (request-to-exit) switch built into a panic bar / exit device, triggered when the bar is pushed.

Wiring REX​

  1. Run a dry contact from the REX device to the door's input port.
  2. Land one side of the REX contact on RXn.
  3. Land the other side on the port's GND pin.
  4. Do not power the REX device from RXn. Most PIR REX sensors and exit-device REX switches need their own power and provide an isolated dry-contact output — use that dry output, not a powered/voltage output.

NO vs NC REX devices​

Most REX devices are momentary normally-open (NO): the contact is open at rest and closes briefly to GND to request exit. That is the common case and is how a push-to-exit button or a PIR REX relay normally behaves.

Some devices supply a normally-closed (NC) output instead. The controller software lets you set how each input is interpreted, so:

  • Match the input's normal state (NO or NC) in the door's software configuration.
  • If a REX appears stuck (door reads "exit requested" constantly, or never responds), confirm the device output type matches the configured input polarity.

Door position sensor (DPS / door contact) on Sn​

The door position sensor tells the controller whether the door is physically open or closed. With a sensor wired, the controller can:

  • Report real-time door open/closed status.
  • Detect a held-open door (open longer than the allowed time).
  • Detect a forced door (opened without a valid credential or REX).

Typical device​

A magnetic reed door contact — recessed (drilled into the door and frame) or surface-mount — is the standard DPS. It is a dry contact that changes state as the magnet (on the door) moves toward or away from the switch (on the frame).

Wiring the door contact​

  1. Run the door contact's two leads to the door's input port.
  2. Land one lead on Sn.
  3. Land the other lead on the port's GND pin.

NO vs NC contact convention​

Magnetic door contacts ship as either normally-open or normally-closed types, and the "normal" state refers to the door being closed (magnet aligned with the switch):

  • A closed-loop / NC contact is the common security convention — the loop is closed when the door is shut and opens when the door opens.
  • An NO contact does the opposite.

Set the sensor polarity in the door's software configuration to match the contact you installed. If "door open" and "door closed" read backward, the configured polarity does not match the physical contact — flip the setting (or the contact type) so closed reads closed.

Verify the inputs​

After wiring, confirm both inputs at the door:

  1. Door sensor: open and close the door while watching the door status in the CAK software. Closed should read closed; open should read open. If it reads backward, fix the sensor polarity in software.
  2. REX: trigger the REX device (wave at the PIR, press the exit button, push the exit bar). The door should unlock for egress, and opening the door on that REX should not raise a forced-door alarm.
  3. Forced / held-open: with the sensor wired, open the door without a credential or REX and confirm a forced-door event; hold it open past the timer and confirm a held-open event.

:::caution REX is an egress convenience, not the life-safety release The controller's REX input is for normal inside exit. It is not the code-required emergency egress release. Where code requires a manual release, the push-to-exit device must interrupt lock power in hardware at the power supply / relay board, independent of the controller (IBC §1010.2.11) — the controller's REX logic is additive to that hardware path, not a substitute. Fail-safe locks (maglocks and similar) must still release on power loss and on fire alarm regardless of REX wiring. See Fire Alarm Integration and Listing & Compliance. :::