Overview: If a postal carrier cannot use an access code, PIN, directory entry, private key, or electronic fob to enter a secured property, the property may need to install a postal lock box so the carrier can open the entry point with an approved postal key.
Important: ButterflyMX does not provide, install, manage, or supply postal lock boxes or postal lock cylinders. The property is responsible for purchasing hardware and coordinating installation with qualified vendors and the local postal carrier.
Purpose
This article explains how postal carrier access works when a property needs a physical key-based entry method alongside ButterflyMX. It covers when a postal lock box may be needed, who is responsible for the hardware, where it is typically installed, and how it is commonly wired.
What Is a Postal Lock Box?
A postal lock box, sometimes called a postal key switch, is a small lockable box installed near a secured entry point such as a vehicle gate, pedestrian gate, or main entrance.
Inside the box is a switch that can be wired to a gate operator, door controller, or access control input. When the postal carrier inserts and turns their approved postal key, the switch activates and sends an open signal to the entry system.
A postal lock box gives authorized postal carriers a separate physical-key method to open a secured gate or door without using ButterflyMX credentials.
When a Postal Lock Box May Be Needed
A postal lock box may be needed when the postal carrier cannot use a standard electronic access method and mail delivery requires access through a locked entrance.
The postal carrier cannot use an access code or PIN.
The mailboxes are located behind a locked gate or secured entrance.
The postal carrier requires approved physical key access.
The property wants postal access to operate separately from resident and visitor access.
Requirements vary by location: Postal access rules differ by country, region, municipality, and postal provider. Always confirm local requirements before purchasing or installing any hardware.
Who Is Responsible?
Party | Responsibility |
Property / HOA / owner / management company | Purchases the postal lock box and arranges mounting and wiring. |
Qualified installer | Installs and wires the box to the gate operator, door controller, or access control system. |
Local postal carrier | May inspect the installation and install or approve the postal lock cylinder, depending on local requirements. |
ButterflyMX | Continues to support resident and visitor access through its normal system, but does not provide or manage the postal lock box. |
Hardware Needed
The property should purchase a commercial postal lock box or postal key switch that meets the requirements of the local postal carrier.
A commonly used example is the DoorKing 1402-080 Postal Lock Box, although the property’s gate contractor, electrician, locksmith, or access control vendor may recommend another compatible model.
Before purchasing, confirm the following
The postal carrier’s lock and box requirements.
Whether the postal carrier provides or installs the lock cylinder.
Whether the selected box is approved for the property’s gate or door application.
Whether any additional local code, authority, or site-specific requirements apply.
Where to Install the Postal Lock Box
The postal lock box should be installed near the secured entry point the carrier needs to access.
For properties using a ButterflyMX intercom, the postal lock box is commonly mounted near the intercom so the access location is easy to find. Final placement should be confirmed by the property’s installer and, when required, the local postal carrier.
Typical installation locations
Near a vehicle gate keypad or intercom pedestal
Near a pedestrian gate entrance
Near a building’s secured main entry
How the Postal Lock Box Works with ButterflyMX
The postal lock box is separate from ButterflyMX credentials and access methods. It does not replace the ButterflyMX intercom, directory, PINs, delivery passes, or resident access.
Instead, it provides an independent way for the postal carrier to trigger the same gate or door to open.
Common operating flow
Residents and visitors use ButterflyMX as usual.
The postal carrier uses the postal lock box.
The carrier inserts and turns their approved postal key.
The switch inside the box activates.
The switch sends an open signal to the gate or door system.
The gate or door opens for postal access.
Result: Postal carrier access remains separate from resident and visitor access, while the same secured entry point can still be opened by either system.
How the Postal Lock Box Is Typically Wired
A qualified gate technician, electrician, locksmith, or access control installer should perform all wiring.
The switch inside the postal lock box is typically wired to the gate operator, door controller, or access control input that triggers the entry point to open.
For gate applications, the postal lock box is commonly wired in parallel with the ButterflyMX relay output so each system can trigger the gate independently.
Do not rely on generic wiring assumptions: Always follow the gate operator, door controller, and access control manufacturer’s instructions. Wiring requirements vary by equipment model and site conditions.
Life-safety and emergency access: Postal lock boxes are not a substitute for fire department lock boxes, Knox boxes, emergency responder access systems, required egress hardware, or other AHJ-mandated life-safety access methods. If the property has separate emergency access requirements, coordinate with the local Authority Having Jurisdiction (AHJ), fire department, gate/door vendor, and qualified installer.
The postal lock box normally functions as a dry-contact switch or similar trigger input, depending on the hardware model. The installer should verify the input type required by the operator or controller and confirm that the postal lock box output matches the equipment specifications.
If the site has multiple controlled entry points, the installer should also confirm which gate or door the postal lock box should activate so postal access is limited to the correct location.
Step-by-Step Setup Process
Confirm access requirements with the local postal carrier.
Verify whether the carrier can use any electronic access method or whether a physical key-based solution is required.
Select an approved postal lock box.
Work with the property’s contractor, electrician, locksmith, or access control vendor to choose a compatible commercial model.
Confirm who provides the lock cylinder.
In many cases, the lock box is purchased empty and the postal carrier installs or approves the cylinder after mounting and wiring are complete.
Install the box near the correct entry point.
Choose a location that is accessible to the carrier and suitable for the gate or door being controlled.
Have a qualified technician wire the box.
The technician should connect the internal switch to the proper gate or door input according to the equipment manufacturer’s instructions.
Coordinate with the local postal carrier.
Once installed, contact the carrier to arrange inspection, approval, or lock cylinder installation if required.
Test the final operation.
Verify that ButterflyMX still works as expected for residents and visitors and that the postal lock box successfully opens the correct gate or door.
Canada Post Guidance
Canada Post has specific delivery access requirements. In many cases, Canada Post does not allow access by combination, punch key, private key, or electronic key fob.
If Canada Post requires access through a locked gate or secured entrance, the property may need to install an approved postal lock box and coordinate with Canada Post for the postal lock cylinder.
Canada Post does not typically provide the postal lock box hardware. The property is generally responsible for purchasing, mounting, and wiring the box before contacting Canada Post to complete the access setup.
Important Notes
Postal lock boxes are separate from ButterflyMX access codes, PINs, delivery passes, and directory access.
Postal lock boxes are also separate from fire department lock boxes, Knox boxes, and emergency responder access systems.
Requirements vary by postal carrier and location.
The property should confirm all requirements before purchasing or installing hardware.
All mounting and wiring should be completed by a qualified technician.
Troubleshooting and Common Misunderstandings
The postal carrier cannot use ButterflyMX credentials
If the postal carrier is not permitted to use an access code, PIN, directory entry, or electronic credential, the property will likely need a physical key-based solution approved by the carrier.
The box was installed, but the postal carrier still cannot access the property
The installation may still require carrier inspection, cylinder installation, or local approval. The property should contact the local postal carrier to confirm the next step.
The property assumes ButterflyMX supplies the postal hardware
ButterflyMX does not provide the postal lock box or lock cylinder. Those items must be sourced and installed by the property and its vendors.
The site uses a gate and an intercom, but the carrier needs a separate entry method
This is a common reason to add a postal lock box. The ButterflyMX system can continue to serve residents and visitors while the postal lock box provides a dedicated access path for mail delivery.
Summary
If a postal carrier cannot use a code, PIN, fob, or directory entry, the property may need to install a postal lock box near the secured entry point.
The property purchases the hardware, a qualified technician mounts and wires it to the gate or door system, and the postal carrier installs or approves the postal lock cylinder when required.
Once complete, the postal carrier can access the property using a physical postal key while residents and visitors continue using ButterflyMX as usual.
FAQ
Does ButterflyMX sell or install postal lock boxes?
No. ButterflyMX does not provide, install, manage, or supply postal lock boxes or postal lock cylinders.
Can a postal lock box work alongside ButterflyMX?
Yes. It is commonly used as a separate access method wired to the same gate or door system, often in parallel with the ButterflyMX relay output.
Who installs the postal lock cylinder?
That depends on the local postal carrier. In many cases, the property installs the empty box and a postal representative later installs or approves the lock cylinder.
Can the property choose any lock box model?
No. The property should first confirm local postal requirements and then select a commercial box that is compatible with both the carrier’s requirements and the site’s entry system.