Understanding UniFi Access Control Hub Input and Output Terminals
UniFi Access Control Hubs easily connect to devices such as locks, chimes, sirens, door position sensors, push-to-exit buttons, motion sensors, and other compatible accessories through their input and output terminals. This article explains how these terminals work to help you set up your access control system effectively. If you have already wired your terminals and are looking for configuration instructions within the UniFi Access application, click here. For hub comparisons, click here.
Inputs
The hub's input terminals enable communication with devices like motion sensors, push-to-exit buttons, door position sensors, and fire panels. These terminals receive signals from the devices and trigger corresponding actions.
Door Hub is used as an example here.
| Input Terminal Name | Description |
| MOTION | Connects to a motion sensor for people detection and automatic door unlocking. See wiring instructions. |
| BUTTON |
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| DOOR POSITION | Connects to a door position sensor (DPS) to monitor a door's open/closed status. See wiring instructions. |
| EMERGENCY | Connects to emergency equipment like fire panels to trigger emergency modes. See emergency modes. |
Note: Terminal names vary by hub type. See the hub installation guides for details: Door Hub, Door Hub Mini, Access Ultra, Enterprise Access Hub, Elevator Hub, and Gate Hub.
Outputs
The hub's output terminals perform actions based on input signals, like unlocking doors, opening doors, ringing chimes, or triggering sirens.
Example 1
Pressing the push-to-exit button unlocks the door lock, and the door operator opens it.
Example 2
Pressing the request-to-entry doorbell button rings a chime and notifies authorized personnel.
Example 3
The door position sensor detecting an unauthorized door opening triggers a siren and displays "Unauthorized Opening" on the user interface.
Lock
The LOCK relay terminals connect to door locks. Learn about selecting UniFi Access Locks and lock wiring instructions.
| Category | Relay Terminal Name | Description |
| LOCK | POWERED | Connects to a lock operating at 12V up to 1 Amp. |
| NO POWER (DRY) | Connects to an electric lock that does not operate at a 12V rating, such as a 24V electric strike. Requires an external transformer. |
AUX
AUX means "auxiliary" and the relay terminals connect to auxiliary devices such as door operators, sirens, and chimes.
| Category | Relay Terminal Name | Description |
| AUX | DOOR OPERATOR | Connects to a door operator needing a dry output signal for activation. See wiring instructions |
| SIREN/CHIME | Connects to a 2-wire siren or chime that operates on 12V with a maximum rating of 0.33A (4 watts). See wiring instructions |
NO, NC, and COM
NC (Normally Closed), NO (Normally Open), and COM (Common) are the three key relay terminals used to control circuits.
- COM: The central terminal that connects to either the NO or NC terminal, depending on the relay's state.
- NO: In its default state (relay off), it remains disconnected from COM, preventing current flow. When the relay is activated, it closes, completing the circuit and allowing current to flow.
- NC: In its default state (relay off), it remains connected to COM, allowing current to flow. When the relay is activated, it opens, breaking the circuit and stopping current flow.
| Relay State | NO & COM Connection | NC & COM Connection |
| Rest State (Relay Off) |
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| Trigger State (Relay On) |
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Typical Device Connections (Inputs & Outputs)
The table below shows common wiring connections based on experience. Actual configurations may vary by device manufacturer.
| Device | Type | Typical Connection to Hub (NO/NC/COM) |
| Fail-safe electric lock | Relay output (activated by hub) | NC/COM on the LOCK terminal |
| Fail-secure electric lock | Relay output (activated by hub) | NO/COM on the LOCK terminal |
| Door operator | Relay output (activated by hub) | NO/COM on the AUX - DOOR OPERATOR terminal |
| Siren/Chime | Relay output (activated by hub) | NO/COM on the AUX - Siren/Chime terminal |
| Door position sensor (DPS) | Dry contact input (sends DPS signal to hub) | Typically NC output* |
| Doorbell button | Dry contact input (sends button press signal to hub) | Typically NO output* |
| Push-to-exit button | Dry contact input (sends button press signal to hub) | Usually selectable (NO/NC, depending on wiring)* |
| Motion sensor | Dry contact input (sends motion detection signal to hub) | Usually selectable (NO/NC, depending on wiring)* |
| Fire panel | Dry contact input (sends fire alarm status to hub) | Usually selectable (NO/NC, depending on wiring)* |
* The hub's input/output terminal settings may require adjustments in the Access application for optimal functionality.