Communicate with ABP End Node without LoRaWAN Network Server --- LG308

1. Introduction

The Dragino LoRaWAN gateway can communicate with LoRaWAN ABP End Node without the need of LoRaWAN server. It can be used in some cases such as:

No internet connection.
User wants to get data forward in gateway and forward to their server base on MQTT/HTTP, etc. (Combine ABP communication method and MQTT forward together).

The basic of this feature is the decoding of LoRaWAN ABP End Node. Requirements:

LoRaWAN End Node in ABP mode. Make sure your end node works in this mode. End node most are default set to OTAA mode
LoRaWAN Gateway model: DLOS8N, LPS8N, LG308N
Firmware version for below instruction: Since LG02_LG08--build-v5.4.1593400722-20200629-1120

2. How it works

Assume we have the LoRaWAN sensor node SN50v3-LB which worksin ABP mode and EU868 band. It has below keys:

AT+DADDR=260B4FC4
AT+APPSKEY=C0 45 F5 97 2D E7 08 CC 65 67 EE A1 1F 07 8A CC
AT+NWKSKEY=05 02 BC BA F0 07 85 71 C2 17 73 70 D1 1F 8A 90

And we have the LPS8N which works in EU868 band and supports ABP decryption. Users can input these keys in the LPS8N so that it can communicate with the SN50v3-LB.

We need to input the above keys in the LPS8N and enable ABP decryption.

2.1 Upstream

Now when this End Node (Dev Addr=260B4FC4) send a uplink packet. When this packet arrive LPS8N, LPS8N will decode it and put the decode data on the file /var/iot/channels/- . So we have this data for further process with other applications in LPS8N.

We can see the log of LPS8N to know this packet arrive.

LPS8N log by "**logread -f** " command

The data of End Node is stored in the file /var/iot/channels/-.
We can use hexdump command to check it.

root@dragino-072185:~# hexdump /var/iot/channels/260B4FC4-0
0000000 4646 4646 4646 4238 3030 3030 3030 3532
0000010 0d48 7fff 03d3 00fe 7000 0000
000001b

RSSI : 4646 4646 4646 4238 = 0xFFFFFFB8 : So RSSI = (0xFFFFFFB8 - 0x100000000) = -72
SNR : 3030 3030 3030 3532 = 0x00000052 = 82, need to divide 10 so SNR is 8.2
Payload : 0x0d48 7fff 03d3 00fe 7000 0000

Notice : The upstream payload length should match the LoRaWAN length requirement (max length depends on Frequency and DR), otherwise the gateway can't decode the payload.

2.1.1 Decode Method

The decode methods — ASCII String and Dragino_LSN50V2_S31 — do not affect how the sensor data is stored; they define how the sensor data should be sent.

For example we have a SN50v3-LB , works in ABP mode and gateway successful get the data, which are:

root@dragino-072185:~# hexdump /var/iot/channels/260B4FC4-0
0000000 4646 4646 4646 4238 3030 3030 3030 3532
0000010 0d48 7fff 03d3 00fe 7000 0000
000001b

If we choose ASCII decoder, the MQTT process will send out with mqtt-data:

Tue Nov 10 03:12:45 2026 user.notice root: [IoT.MQTT]:pub_topic[-t]: dragino-072185/260B4FC4/uplink
Tue Nov 10 03:12:45 2026 user.notice root: [IoT.MQTT]:decoder: ASCII
Tue Nov 10 03:12:45 2026 user.notice root: [IoT.MQTT]:mqtt_data[-m]: ffffffb0000000500d487fff03d700fe700000

If we choose Dragino_LSN50V2_S31 decoder, the MQTT process will send out with mqtt-data

Tue Nov 10 03:08:14 2026 user.notice root: [IoT.MQTT]:pub_topic[-t]: dragino-072185/260B4FC4/uplink
Tue Nov 10 03:08:14 2026 user.notice root: [IoT.MQTT]:decoder: Dragino_LSN50V2_S31
Tue Nov 10 03:08:14 2026 user.notice root: [IoT.MQTT]:mqtt_data[-m]: {"BatV":3.4,"SNR":7.2,"EXTI_Trigger":"FALSE","Illum":-400,"MODE":0,"ADC_CH0V":0.98,"Work_mode":"IIC","RSSI":-79,"Digital_IStatus":"Low","TempC1":3276.7,"Door_status":"OPEN"}

Above scripts are store in /etc/lora/decoder/. User can put their scripts here and select it in the UI.

2.1.2 How to Decode My End Node

1. Configure the ABP keys for your end node in the gateway. enable ABP decode in Web UI

2. Don't choose MQTT service, use LoRaWAN.

3. When your end node send a message to the gateway, there will be a file store in /var/iot/channels. full path should be /var/iot/channels/-

4. Use the /etc/lora/decoder/Dragino_LSN50V2_S31 as template to decode your payload. This script is written in Lua language. User can manually call this script when you see the data file in /var/iot/channels by running:

/etc/lora/decoder/Dragino_LSN50V2_S31 <DevAddr>-<sequence>

5. What you see as output is the MQTT data device will upload, user's end node has different payload compare with LHT65, most properly this file will report with error. User need to modify to match the actual payload.

2.2 Downstream

In LPS8N, we can create a file in the directory /var/iot/push for downstream purpose. We recommend using each command to generate this file. This file will be used for transmission and auto-deleted after used

The file should use below format:

dev_addr,imme/time,txt/hex,payload

Since fimware > Dragino lgw--build-v5.4.1668567157 . Support more option

dev_addr,imme/time,txt/hex,payload,txpw,txbw,SF,frequency,rxwindow,Fport

dev_addr: Inptu the device address
imme/time:
- imme: send downstream immediately,For Class C end node.
- time: send downstream after receive device's uplink. For Class A end node
txt/hex:
- txt: send payload in ASCII
- hex: send payload in HEX
payload: payload to be sent, payload lenght should match the LoRaWAN protocol requirement.
txpw: Transmit Power. example: 20
txbw: bandwidth:
- 1: 500 kHz
- 2: 250 kHz
- 3: 125 kHz
- 4: 62.5 kHz
SF: Spreading Factor : SF7/SF8/SF9/SF10/SF11/SF12
Frequency: Transmit Frequency: example: 923300000
rxwindow: transmit on Rx1Window or Rx2Window.
Fport: Transmit port,example:8

Completely exmaple:

Old version: echo 018193F4,imme,hex,0101 > /var/iot/push/test
New version: echo 018193F4,imme,hex,0101,20,1,SF12,923300000,2,8 > /var/iot/push/test

DownstreamFrequency:

The LPS8N will use the RX2 window info to send the downstream payload, use the default LoRaWAN settings, as below:

EU868: 869.525Mhz, DR0(SF12BW125)
US915: 923.3Mhz, SF12 BW500
CN470: 505.3Mhz, SF12 BW125
AU915: 923.3Mhz, SF12 BW500
AS923: 923.2Mhz, SF10 BW125
KR920: 921.9Mhz, SF12 BW125
IN865: 866.55Mhz, SF10 BW125
RU864: 869.1Mhz, SF12 BW125

Examples:

A downlink file can be created with the echo command:

root@dragino-072185:~# echo 260B4FC4,imme,hex,1234 > /var/iot/push/text

The gateway log shows the command being detected and processed:

Wed Nov 11 03:24:11 2026 daemon.info fwd[13398]: [INFO~][DNLK]Looking file : text
Wed Nov 11 03:24:11 2026 daemon.info fwd[13398]: [INFO~][DNLK] Pending IMMEDIATE downlink for 260B4FC4
Wed Nov 11 03:24:11 2026 daemon.info fwd[13398]: [INFO~][DNLK]customer immediate downlink for 260B4FC4 ready

The downlink is then transmitted, which is confirmed by:

Wed Nov 11 03:24:12 2026 daemon.info fwd[13398]: [INFO~][JIT] send done on rf_chain 0 in count_us=3010302237 with freq=869525000, SF12

3) and the end node will got:

Receive data
BuffSize:2,Run AT+RECVB=? to see detail
AT+RECVB=?
2:12 34 

OK

3. Example 1: Communicate with LT-22222-L

Script can be download from: Example Script 1

#!/bin/sh
# This scripts shows how to use LPS8/LG308/DLOS8 to communicate with two LoRaWAN End Nodes, without the use of internet or LoRaWAN server
#
# Hardware Prepare:
## 1. LT-22222-L x 2, both are configured to work in
#   a) Class C ;
# b) ABP Mode ;
# c) AT+Mod=1
## 2. LPS8,
#   a) Firmware version >
#   b) Input the LT-22222-L keys in LPS so LPS8 can talk with them.
#   c) Lorawan server choose built-in
#   d) in Custom page, select custom script to point to this script. (put this script in /etc/iot/scripts directory)
#
# How it works?
#   a) Devices 1 sends a uplink payload to LPS8. LPS8 will get the DI1 and DI2 info from the payload
#   b) LPS8 will send a message to Device 2 to set the Device2 DO1 = Device1 DI1, and Device DO2 = Device DI2.
#   c) Device2 will change DO1 and DO2 to according to the message from LPS8, and send back a message to LPS8 with the its DO1
#   and DO2 value. LPS8 will ask Device1 to change its DO1 to same as Device 2, and change the DO2 to the same as Device 2.
#   ( The purpose of this step is to show that the Device2 has already do the change there).
#
#  For example: If current status of Device1 and Device2 leds shows:
#  Device1: DI1: ON, DI2: ON , DO1: OFF,  DO2: OFF
#  Device2: DI1: OFF, DI2: OFF , DO1: OFF,  DO2: OFF
#
#  Step2  will cause below change:
#  Device1: DI1: ON, DI2: ON , DO1: OFF,  DO2: OFF
#  Device2: DI1: OFF, DI2: OFF , DO1: ON,  DO2: ON
#
#  Step3 will cause below change:
#  Device1: DI1: ON, DI2: ON , DO1: ON,  DO2: ON
#  Device2: DI1: OFF, DI2: OFF , DO1: ON,  DO2: ON
#  So if a person is in the Device 1 location, he can check if the DO LED match DI LEDs on Device 1 to confirm
#  whether the Device 2 has been changed.//