# Wireless M-Bus USB dongle problem

**URL:** <https://discourse.nodered.org/t/wireless-m-bus-usb-dongle-problem/89987>\
**Category:** Hardware\
**Tags:** node-red-node-serialport, m-bus\
**Created:** [4 August 2024 18:00 UTC](https://discourse.nodered.org/t/wireless-m-bus-usb-dongle-problem/89987 "2024-08-04T18:00:13Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![werneroostendorp](https://avatars.discourse-cdn.com/v4/letter/w/35a633/32.png) [@werneroostendorp](https://discourse.nodered.org/u/werneroostendorp)\
**Post date:** [4 August 2024 18:00 UTC](https://discourse.nodered.org/t/wireless-m-bus-usb-dongle-problem/89987/1 "2024-08-04T18:00:13Z")

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I have connected an IMST PA-iM871A Wireless M-Bus dongle to my PC (Windows). I have installed the drivers correctly because the provided software recognizes the USB stick.

Now, I want to connect to an M-Bus device (a gas meter) via Node-Red. For this, I am using the node-serialport ([node-red-node-serialport (node) - Node-RED](https://flows.nodered.org/node/node-red-node-serialport)).

The flow consists of a serial in and a serial out node, configured to connect to my USB dongle. This seems to work well because the green 'connected' indicator is on, and it changes to 'disconnected' when I unplug the USB stick from my computer.

What I want to do now is communicate with my dongle. I have tried various methods to send data via an inject node, but nothing seems to work. Can anyone help me figure out how to send a message to the dongle and receive a message from it? (for example, receive the name of the dongle in Node-Red) Thanks in advance

Here is the flow:

[  
{  
"id": "d1b0c0e0.7b6a7",  
"type": "tab",  
"label": "Flow 1",  
"disabled": false,  
"info": ""  
},  
{  
"id": "e1b0d3f7.a2c4e",  
"type": "serial in",  
"z": "d1b0c0e0.7b6a7",  
"name": "",  
"serial": "2aec20f3b4664b5e",  
"x": 270,  
"y": 440,  
"wires": [  
[  
"1b0c2e27.6e3ba2"  
]  
]  
},  
{  
"id": "1b0c2e27.6e3ba2",  
"type": "debug",  
"z": "d1b0c0e0.7b6a7",  
"name": "",  
"active": true,  
"tosidebar": true,  
"console": false,  
"tostatus": false,  
"complete": "payload",  
"x": 590,  
"y": 440,  
"wires":   
},  
{  
"id": "261fd38a6e1260a0",  
"type": "serial out",  
"z": "d1b0c0e0.7b6a7",  
"name": "",  
"serial": "2aec20f3b4664b5e",  
"x": 570,  
"y": 360,  
"wires":   
},  
{  
"id": "0d53a28c830a68d3",  
"type": "inject",  
"z": "d1b0c0e0.7b6a7",  
"name": "",  
"props": [  
{  
"p": "payload"  
},  
{  
"p": "topic",  
"vt": "str"  
}  
],  
"repeat": "",  
"crontab": "",  
"once": false,  
"onceDelay": 0.1,  
"topic": "",  
"payload": "",  
"payloadType": "date",  
"x": 300,  
"y": 360,  
"wires": [  
[  
"261fd38a6e1260a0"  
]  
]  
},  
{  
"id": "2aec20f3b4664b5e",  
"type": "serial-port",  
"name": "",  
"serialport": "COM4",  
"serialbaud": "115200",  
"databits": "8",  
"parity": "none",  
"stopbits": "1",  
"waitfor": "",  
"dtr": "none",  
"rts": "none",  
"cts": "none",  
"dsr": "none",  
"newline": "100",  
"bin": "bin",  
"out": "time",  
"addchar": "",  
"responsetimeout": "10000"  
}  
]

---

<div class="post-metadata">

**Author:** ![werneroostendorp](https://avatars.discourse-cdn.com/v4/letter/w/35a633/32.png) [@werneroostendorp](https://discourse.nodered.org/u/werneroostendorp)\
**Post date:** [2 October 2024 19:00 UTC](https://discourse.nodered.org/t/wireless-m-bus-usb-dongle-problem/89987/2 "2024-10-02T19:00:19Z")

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I am still trying to get some data in Node-Red from the iM871A-USB - Wireless M-Bus USB-adapter. The adapter is working fine because i checked it via a Analyzer tool in Windows, and i receive telegram messages. But i need the telegrams in Node Red, and tried so many things for almost 2 months right now. Hope someone can help me out! 🙂

It's this device: [iM871A-USB - Wireless M-Bus USB-adapter 868 MHz | IMST GmbH](https://shop.imst.de/wireless-solutions/usb-radio-products/10/im871a-usb-wireless-m-bus-usb-adapter-868-mhz?c=14)

Document about the Host controller interface

> **[WMBus\_HCI\_Spec\_V1\_6.pdf](https://shop.imst.de/media/pdf/1b/e2/64/WMBus_HCI_Spec_V1_6.pdf)**
>
> 1194.38 KB

I tried to use the serial in / serial out node, connected with an inject node and a debug node. But nothing happens. Hope someone can help me a bit.

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<div class="post-metadata">

**Author:** ![zubairsk](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/zubairsk/32/94222_2.png) [@zubairsk](https://discourse.nodered.org/u/zubairsk)\
**Post date:** [25 November 2024 15:17 UTC](https://discourse.nodered.org/t/wireless-m-bus-usb-dongle-problem/89987/3 "2024-11-25T15:17:09Z")

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You need to send a valid M-Bus frame to the device to communicate with your IMST PA-iM871A Wireless M-Bus dongle in Node-RED. Use a `function` node to craft the appropriate data (e.g., as a byte array) and send it via the `serial out` node. The `inject` node can trigger this action, but ensure you send the correct M-Bus command rather than just a random payload. Use the `serial in` node to receive responses from the dongle and debug the incoming data with a `debug` node. Ensure your serial port settings (COM port, baud rate, etc.) match the dongle's configuration. Check the dongle's documentation for specific command sequences.

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [23 February 2025 15:17 UTC](https://discourse.nodered.org/t/wireless-m-bus-usb-dongle-problem/89987/4 "2025-02-23T15:17:48Z")

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