> For the complete documentation index, see [llms.txt](https://help.security.gallagher.com/smb/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.security.gallagher.com/smb/installing-gallagher-smb/installing-the-hardware/gallagher-hbus.md).

# Gallagher HBUS

To enable a more efficient and resilient device communication framework, Gallagher developed **HBUS**—a proprietary high-speed RS-485 protocol engineered for advanced IoT-based security architectures.

HBUS provides secure, deterministic, and low-latency communication between field devices, ensuring accurate data transfer and robust system performance. Designed for scalability and resilience, it supports seamless integration with existing site infrastructure through full backward compatibility.

This purpose-built protocol optimizes bandwidth utilization, enhances fault tolerance, and strengthens cybersecurity across the Gallagher ecosystem—delivering reliable, high-speed connectivity .

<details>

<summary><mark style="color:orange;"><strong>High-Speed Performance</strong></mark> </summary>

Gallagher’s HBUS protocol runs on the **RS-485 serial bus** and operates at 1 Mb/s. This is substantially faster than other RS-485 based communications protocols which typically operate at a maximum speed of 38.4 Kb/s.

With a maximum speed difference of 96% over other protocols, HBUS delivers a substantially faster response time than other access control solutions.

</details>

<details>

<summary><mark style="color:orange;"><strong>Built-In Security and Encryption</strong></mark></summary>

HBUS delivers **plug-and-play encrypted communications**—no manual key management required. Each device is factory-loaded with Elliptic Curve P-256 certificates to prevent counterfeits, while shared and AES-128 session keys are securely generated and refreshed daily.

Unlike Wiegand or OSDP, HBUS is inherently secure, with continuous heartbeats to detect tampering and RS-485 connectivity that eliminates exposed Ethernet ports.

</details>

<details>

<summary><mark style="color:orange;"><strong>Communication</strong></mark></summary>

HBUS enables **bi-directional data exchange** between controllers and devices, creating an adaptive, responsive network that supports automated decisions and continuous status monitoring for maintenance and alarms.

</details>

<details>

<summary><mark style="color:orange;"><strong>Configuration &#x26; Maintenance</strong></mark></summary>

Unlike many IP based edge field devices, HBUS devices require **no IT networking knowledge** to install and configure. HBUS devices can be configured in **SMB Installer Portal** in advance, allowing quick ‘plug and play’ installation for the field installer.

As HBUS devices regularly communicate to the Controller, their status can be easily monitored for maintenance and alarms purposes.

</details>

<details>

<summary><mark style="color:orange;"><strong>Firmware Updates</strong></mark></summary>

Firmware is **automatically upgraded** at the device.

The capacity to upgrade firmware without taking devices offline delivers operational continuity and significantly speeds up an installer’s time upgrading devices.

</details>

<details>

<summary><mark style="color:orange;"><strong>Cable Specification</strong></mark></summary>

The maximum permissible cable length is **500m (1640ft)** using standard RS485 cable. Non-standard cable shielded cable will reduce the maximum cable length.

</details>

<details>

<summary><mark style="color:orange;"><strong>Connections</strong></mark></summary>

A maximum of **80 HBUS devices** may be connected to a Controller, shared over all HBUS ports. In addition, each device type has an individual limit.

Devices may be connected in '**daisy-chain**' format or individually via an 8 Port Hub.

</details>

<details>

<summary><mark style="color:orange;"><strong>8 Port Hub</strong></mark></summary>

Should you require multiple doors, the HBUS 8 Port Hub can be utilized.

This hub supports the star wiring of eight HBUS devices to the hub’s eight ports.

Note that you will still need to provide power to the door. &#x20;

</details>

<details>

<summary><mark style="color:orange;"><strong>Unique Identifiers</strong></mark> </summary>

Gallagher’s HBUS protocol assigns **unique identifiers** to every field device, enabling controllers to verify each device’s identity with confidence. This architecture supports **automatic device recognition** and simple authentication, delivering true plug-and-play operation with minimal configuration.

</details>


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