AN-305 LoRaWAN Door/Window Contact Sensor User Guide

Device Information: Model AN-305, devEui ffffff100004bcf0, gateway IP 192.168.31.193, Modbus Slave ID 2, BACnet Device ID 101

1 Protocol Overview

The AN-305 reports door/window open-close state, open-close event, battery voltage, tamper status, and signal quality on Fport 210.

Payload format (Fport 210):

Byte Field Description
0 Reserved Always 0x00 (protocol version)
1 … N TLV pairs [Type(1 B)][Value(N B)] … repeating until end

Each Type byte determines the field name and the number of following value bytes:

Type Value Bytes Field Name Encoding Scale Unit Notes
0x01 1 model uint8 Model code = 0x24 or 0x25
0x76 1 doorState uint8 0=closed 1=open (state, primary)
0x18 1 doorState uint8 0=closed 1=open (state, alternate)
0x24 1 doorEvent uint8 0=close event 1=open event triggered
0x77 1 tamperState uint8 0=normal 1=tampered
0x04 2 batteryVoltage uint16 BE ÷1000 V mV raw ÷1000 = V
0x05 1 batteryLowEvent uint8 0=normal 1=low-voltage event
0x03 1 tamperEvent uint8 0=normal 1=tamper event

JavaScript Decoder Example:

// AN-305 Door/Window Contact Sensor — Fport 210 uplink decoder
function decodeUplink(bytes) {
  var i = 1, r = {};
  function u16(b,o){ return (b[o]<<8)|b[o+1]; }
  while (i < bytes.length) {
    var t = bytes[i++];
    switch (t) {
      case 0x01: r.model           = bytes[i++]; break;
      case 0x03: r.tamperEvent     = bytes[i++]; break;
      case 0x04: r.batteryVoltage  = u16(bytes,i)/1000; i+=2; break;
      case 0x05: r.batteryLowEvent = bytes[i++]; break;
      case 0x18: r.doorState       = bytes[i++]; break; // 0=closed  1=open
      case 0x24: r.doorEvent       = bytes[i++]; break; // 0=close event  1=open event
      case 0x76: r.doorState       = bytes[i++]; break; // same meaning, primary field
      case 0x77: r.tamperState     = bytes[i++]; break;
      default:   i++; break;
    }
  }
  return r;
}
// Example payload (hex): 00 01 24 76 01 24 01 77 00 04 0D AC 05 00
// → { model:36, doorState:1, doorEvent:1, tamperState:0, batteryVoltage:3.50, batteryLowEvent:0 }

Script download: LPP.zip

Compatibility note: LPP.js is developed and tested against ChirpStack v4.17.0. The ChirpStack JavaScript codec API may differ across versions — if you are running a different ChirpStack version, review and adjust the script as needed before deployment.
⚠️ The IP addresses (192.168.31.205 / 192.168.31.193), ChirpStack API token, Slave ID, BACnet Device ID, and devEui in the examples below are for demonstration only. Replace them with your actual gateway IP, ChirpStack API token, and device parameters.

2.1 ChirpStack MQTT Subscription

Subscribe to the MQTT topic to receive real-time uplink frames:

Application ID3ef9e6b9-ec54-4eda-86b8-a5fb46899f39 is the factory-default ChirpStack
application built into the gateway. Replace it with your actual application
ID if you have created a different one.

Gateway IP192.168.31.193 is the gateway WAN port IP shown as an
example. Replace it with your actual gateway IP address.

Device EUIffffff100004bcf0 is the EUI of the example device.
Replace it with the EUI shown in the gateway device list, or use +
as a wildcard to subscribe to all devices at once.
# Subscribe to one specific device
mosquitto_sub -h 192.168.31.193 -p 1883 \
  -u gateway -P mqtt88888888 \
  -t "application/3ef9e6b9-ec54-4eda-86b8-a5fb46899f39/device/ffffff100004bcf0/event/up"

# Subscribe to ALL devices on ALL applications (wildcard)
mosquitto_sub -h 192.168.31.193 -p 1883 \
  -u gateway -P mqtt88888888 \
  -t "application/+/device/+/event/up"

Example uplink payload (JSON):

{
  "devEui": "ffffff100004bcf0",
  "fPort": 210,
  "object": {
    ...  (decoded LPP fields)
  }
}

2.2 IoT Hub HTTP API

Send a GET request to retrieve the latest device state:

curl -s "http://192.168.31.193:8070/api/getStatus?devEui=ffffff100004bcf0"
{
  "success": true,
  "result": {
    "doorState": 1,
    "batteryVoltage": 3,
    "batteryVoltageState": 0,
    "tamperStatus": true,
    "model": "AN-305"
  }
}

2.3 IoT Hub Modbus TCP — Python Script

Script download: modbus_tcp_read.py

Use modbus_tcp_read.py to poll all registers at once:

python3 modbus_tcp_read.py --ip 192.168.31.193 --port 502 \
    --slaveId 2 --sensorType AN-305
Target: 192.168.31.193:502 | Slave ID: 2 | Sensor: AN-305
================================================================================================================================================================
Attribute                | Addr   | FC  | Format     | Order        | Cnt | Scale    | Raw(Hex)            | Value              | Unit
----------------------------------------------------------------------------------------------------------------------------------------------------------------
online                   | 6      | 03  | Bit/Bool   | Big(ABCD)    | 1   | x1       | 0001                | true               | none
lastOnlineTime           | 7      | 03  | UnixTime   | Big(ABCD)    | 2   | x1       | 69CC C6F5           | 1775027957         | second
doorState                | 9      | 03  | Int16      | Big(ABCD)    | 1   | x1       | 0001                | 1.0                | none
batteryVoltage           | 10     | 03  | Int16(S)   | Big(ABCD)    | 1   | /100     | 012C                | 3.00               | volt
batteryVoltageState      | 11     | 03  | Int16      | Big(ABCD)    | 1   | x1       | 0000                | 0.0                | none
tamperStatus             | 12     | 03  | Bit/Bool   | Big(ABCD)    | 1   | x1       | 0001                | true               | none
batteryLevel             | 13     | 03  | Int16      | Big(ABCD)    | 1   | x1       | 0000                | 0.0                | percent
tamperEvent              | 14     | 03  | Int16      | Big(ABCD)    | 1   | x1       | 0000                | 0.0                | none
doorEvent                | 15     | 03  | Int16      | Big(ABCD)    | 1   | x1       | 0000                | 0.0                | none
model                    | 40     | 03  | String(24B) | ASCII        | 12  | x1       | 414E 2D33 3035 0000 ... | AN-305             | none
rssi                     | 52     | 03  | Int16      | Big(ABCD)    | 1   | x1       | FFB2                | -78.0              | none
snr                      | 53     | 03  | Int16      | Big(ABCD)    | 1   | x1       | 0009                | 9.0                | none

2.4 IoT Hub Modbus TCP — Modbus Poll

Tool download: Modbus Poll 9.5.0.1507.zip

  1. Open Modbus Poll, connect to 192.168.31.193:502, Slave ID 2
  2. Menu Setup → Read/Write Definition, set Function Code = FC03, Start Address = 6, Length = 48
  3. Click OK — values update in real-time

2.5 IoT Hub BACnet BIP — Python Script

Script download: bacnet_read.py

Use bacnet_read.py to read all BACnet objects:

python3 bacnet_read.py --ip 192.168.31.193 --port 47808 --id 101
Target: 192.168.31.193:47808 | BACnet ID: 101 | Scan: 10100-10199
------------------------------------------------------------
Type | Instance | Offset | Value                    | Object Name
------------------------------------------------------------
BI   | 10102    | 2      | active                   | ffffff100004bcf0.online
AI   | 10103    | 3      | 1775027968.00            | ffffff100004bcf0.lastOnlineTime
BI   | 10104    | 4      | active                   | ffffff100004bcf0.doorState
AI   | 10105    | 5      | 3.00                     | ffffff100004bcf0.batteryVoltage
AI   | 10106    | 6      | 0.00                     | ffffff100004bcf0.batteryVoltageState
BI   | 10107    | 7      | active                   | ffffff100004bcf0.tamperStatus
AI   | 10108    | 8      | 0.00                     | ffffff100004bcf0.batteryLevel
AI   | 10109    | 9      | 0.00                     | ffffff100004bcf0.tamperEvent
AI   | 10110    | 10     | 0.00                     | ffffff100004bcf0.doorEvent
CV   | 10114    | 14     | AN-305                   | ffffff100004bcf0.model
AI   | 10115    | 15     | -78.00                   | ffffff100004bcf0.rssi
AI   | 10116    | 16     | 9.00                     | ffffff100004bcf0.snr

2.6 IoT Hub BACnet BIP — YABE

Tool download: SetupYabe_v2.1.0.exe

  1. Open YABE, connect to 192.168.31.193:47808
  2. Expand Device 101 in the device tree
  3. Browse AI/BI/AV/BV/CV objects to view real-time values