> For the complete documentation index, see [llms.txt](https://support.powerio.com/hub/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://support.powerio.com/hub/security/security-en/operation/netzwerk-und-bms.md).

# Network and BMS Communication

This page describes the connection to building management technology (BMS) from a security perspective. The complete protocol description is available on the products’ fieldbus pages.

## Interfaces and protocols by product

{% tabs %}
{% tab title="H1.M100" %}
**Interfaces:** Ethernet and serial communication

**BMS:** Modbus TCP/RTU via a suitably configured application, for example CODESYS. BACnet/IP is optionally possible via CODESYS.

**Cellular:** Not integrated
{% endtab %}

{% tab title="H1.M200" %}
**Interfaces:** Ethernet and serial communication

**BMS:** Modbus TCP/RTU via a suitably configured application, for example CODESYS. BACnet/IP is optionally possible via CODESYS.

**Cellular:** The H1.M200-CDS-LTE variant has an LTE module with a SIM card slot.
{% endtab %}

{% tab title="H1.M300" %}
**Interfaces:** Ethernet and four RS485 interfaces

**BMS:** Modbus TCP/RTU and Modbus gateway in the device firmware. BACnet/IP is optionally possible via CODESYS.

**Cellular:** Not integrated
{% endtab %}

{% tab title="T1.B100" %}
**Interfaces:** 100 Mbit/s Ethernet, four serial onboard ports and an expansion slot

**BMS:** Modbus TCP/RTU and Modbus gateway in the device firmware. BACnet/IP is optionally possible via CODESYS.

**Cellular:** Not integrated
{% endtab %}
{% endtabs %}

The documented solution for BACnet/IP uses the [HVAC BACnet2 Library](/hub/codesys-hvac/en/hvac-bacnet2-library/beschreibung.md) with a compatible CODESYS Runtime and a separate [CODESYS BACnet SL license](https://store.codesys.com/en/codesys-bacnet-sl.html). BACnet MS/TP, BACnet/SC and Modbus Security are not generally approved for the listed devices.

{% hint style="warning" %}
Modbus TCP, Modbus RTU and classic BACnet/IP do not provide encryption or user login themselves. They must be operated in protected automation networks. For untrusted networks, segmentation, firewall rules, and a secured tunnel such as VPN or TLS are required.
{% endhint %}

## Recommendations for operation

* Operate controllers in their own segmented automation network
* Not required [Disable access services](/hub/security/security-en/device/zugriff-und-authentifizierung.md)
* [Enable HTTPS for the web interface](/hub/security/security-en/device/verschluesselung-und-zertifikate.md)
* Remote access via VPN

## LTE and SIM

{% columns %}
{% column %}

### Device function

H1.M200-CDS-LTE supports a SIM card and an LTE connection. The SIM card PIN query must be disabled. The device software supports APN configuration as well as PAP or CHAP authentication, if required by the mobile network operator.
{% endcolumn %}

{% column %}

### Security classification

PAP and CHAP are used for access authentication and do not encrypt user data. The radio link encryption is negotiated by the SIM, modem, and mobile network. Application data must additionally be secured with HTTPS, VPN, or a comparable end-to-end protection.
{% endcolumn %}
{% endcolumns %}


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