General Configure for -NB & -NS models (NB-IoT)

1. The use of this guideline

This configure instruction is for Dragino NB-IoT models with -NB or -NS suffix, for example DDS75-NB. These models use the same NB-IoT Module BC660K-GL and has the same software structure. The have the same configure instruction to different IoT servers. Use can follow the instruction here to see how to configure to connect to those servers.

2. Attach Network

2.1 General Configure to attach network

To attache NB-IoT sensors to NB-IoT Network, You need to:

1. Get a NB-IoT SIM card from Service Provider. (Not the same as the SIM card we use in mobile phone)
2. Power Off End Node ( See below for the power off/on position)
3. Insert the SIM card to Sensor. ( See below for direction)
4. Power On End Node
5. Configure APN in the sensor (AT+APN=<APN>, example AT+APN=iot.1nce.net

After doing above, the NB-IoT Sensors should be able to attach to NB-IoT network .

The -NB and -NS models support LTE Cat NB2, with below frequency band: multiple frequency bands of B1/B2/B3/B4/B5/B8/B12/B13/B14/B17/B18/B19/B20/B25/B28/B66/B70/B85 . Make sure you use a the NB-IoT SIM card.

SIM Provider

AT+APN=

NB-IoT Coverage Comments 1NCE

iot.1nce.net

Coverage Reference Link

Austria, Belgium, Bulgaria, Croatia, Czech Republic, Denmark, Finland, Germany, Great Britain, Greece, Hungary, Ireland, Italy, Latvia, Malta, Netherlands, Norway, Puerto Rico, Russia, Slovak , Republic, Slovenia, Spain, Sweden, Switzerland, Taiwan, USA, UK, US Virgin Islands

UK: Band20

China Mobile

No need configure

China Mainland, HongKong

 

China Telecom

ctnb

China Mainland

 

SIM Provider

AT+QCGDEFCONT=

Command Explanation Comments 1NCE/NB card purchased by the customer

iot.1nce.net/xxx

This command sets the PSD connection settings for PDN connection on power-up. When the MT attaches to the NB-IoT network on power-on, a PDN connection setup is performed. Therefore, PDN connection settings are stored in NVRAM so that they can be used by the modem during the attachment.

 

2.2 Speed Up Network Attach time

BC660K-GL supports multi bands B1/B2/B3/B4/B5/B8/B12/B13/B14/B17/B18/B19/B20/B25/B28/B66/B70/B85.  It will search one by one and try to attach, this will take a lot of time and even cause attach fail and show Signal Strenght:99. User can lock the band to specify band for its operator to make this faster. 

AT+QBAND?        // Check what is the current used frequency band
AT+QBAND=1,4     // Set to use 1 frequency band. Band4
Europe General AT+QBAND=2,8,20  // Set to use 2 frequency bands. Band 8 and Band 20
Global General : AT+QBAND=10,8,20,28,2,4,12,13,66,85,5

Verizon       AT+QBAND=1,13
AT&T           AT+QBAND=3,12,4,2
Telstra        AT+QBAND=1,28
Softband     AT+QBAND=2,3,8

After connection is successful, user can use AT+QENG=0  to check which band is actually in used.

By default, device will search network for 5 minutes. User can set the time to 10 minutes by AT+CSQTIME=10 so it can search longer.

See bands used for different provider: NB-IoT Deployment , Bands, Operator list

3. Configure to connect to different servers

3.1 General UDP Connection

The NB-IoT Sensor can send packet to server use UDP protocol. 

3.1.1 Simulate UDP Connection by PC tool

We can use PC tool to simulate UDP connection to make sure server works ok. 

3.1.2 Configure NB-IoT Sensor

3.1.2.1 AT Commands

AT Commands:

• AT+PRO=2,0         //  Set to use UDP protocol to uplink ,Payload Type select Hex payload

• AT+SERVADDR=120.24.4.116,5601      //  Set UDP server address and port

3.1.2.2 Uplink Example

3.2 General MQTT Connection

The NB-IoT Sensor can send packet to server use MQTT protocol. 

Below are the commands.

AT Commands:

• AT+PRO=3,0      //  Set to use MQTT protocol to uplink, Payload Type select Hex payload.

• AT+SERVADDR=120.24.4.116,1883        //  Set MQTT server address and port

• AT+CLIENT=CLIENT                                 //  Set up the CLIENT of MQTT

• AT+UNAME=UNAME                              //  Set the username of MQTT

• AT+PWD=PWD                                        //  Set the password of MQTT

• AT+PUBTOPIC=NSE01\_PUB                    //  Set the sending topic of MQTT

• AT+SUBTOPIC=NSE01\_SUB                    //  Set the subscription topic of MQTT

Notice: MQTT protocol has a much higher power consumption compare with UDP/CoAP protocol. Please check the power analyze document and adjust the uplink  period to a suitable interval.

3.3 ThingSpeak (via MQTT)

3.3.1 Get MQTT Credentials

ThingSpeak connection uses MQTT Connection. So we need to get MQTT Credentials first. You need to point MQTT Devices to ThingSpeak Channel as well. 

3.3.2 Simulate with MQTT.fx

3.3.2.1 Establish MQTT Connection

After we got MQTT Credentials, we can first simulate with PC tool MQTT.fx tool to see if the Credentials and settings are fine. 

• Broker Address: mqtt3.thingspeak.com

• Broker Port: 1883

• Client ID: <Your ThingSpeak MQTT ClientID>

• User Name: <Your ThingSpeak MQTT User Name>

• Password: <Your ThingSpeak MQTT Password>

3.3.2.2 Publish Data to ThingSpeak Channel

In MQTT.fx, we can publish below info:

• Topic: channels/YOUR_CHANNEL_ID/publish

• Payload: field1=63&field2=67&status=MQTTPUBLISH 

Where 63 and 67 are the value to be published to field1 & field2. 

Result: 

3.3.3 Configure NB-IoT Sensor for connection

3.3.3.1 AT Commands:

In the NB-IoT, we can run below commands so to publish the channels like MQTT.fx

• AT+PRO=3,1     // Set to use ThingSpeak Server and Related Payload

• AT+CLIENT=<Your ThingSpeak MQTT ClientID>

• AT+UNAME=<Your ThingSpeak MQTT User Name>

• AT+PWD=<Your ThingSpeak MQTT Password>

• AT+PUBTOPIC=<YOUR\_CHANNEL\_ID>

• AT+SUBTOPIC=<YOUR\_CHANNEL\_ID>

3.3.3.2 Uplink Examples

For SE01-NB

For DDS20-NB

For DDS45-NB

For DDS75-NB

For NMDS120-NB

For SPH01-NB

For NLM01-NB

For NMDS200-NB

For CPN01-NB

For DS03A-NB

For SN50V3-NB

3.3.3.3 Map fields to sensor value

When NB-IoT sensor upload to ThingSpeak. The payload already specify which fileds related to which sensor value. Use need to create fileds in Channels Settings. with name so to see the value correctly. 

Below is the NB-IoT Product Table show the mapping. 

 

Field1

Field2

Field3

Field4

Field5

Field6

Field7

Field8

Field9

Field10

S31x-NB

Temperature 

Humidity

Battery

RSSI

 

 

 

 

 

 

SE01-NB

Temperature 

Humidity

conduct

dielectric_constant

Battery

RSSI

 

 

 

 

DDS20-NB

distance

Battery

RSSI

 

 

 

 

 

 

 

DDS45-NB

distance

Battery

RSSI

 

 

 

 

 

 

 

DDS75-NB

distance

Battery

RSSI

 

 

 

 

 

 

 

NMDS120-NB

distance

Battery

RSSI

 

 

 

 

 

 

 

SPH01-NB

ph

Temperature

Battery

RSSI

 

 

 

 

 

 

NLM01-NB

Humidity

Temperature

Battery

RSSI

 

 

 

 

 

 

NMDS200-NB

distance1

distance2

Battery

RSSI

 

 

 

 

 

 

CPN01-NB

alarm

count

door open duration

calc flag

Battery

RSSI

 

 

 

 

DS03A-NB

level

alarm

pb14door open num

pb14 last open time

pb15 level status

pb15 alarm status

pb15 door open num

pb15 last open time

Battery

RSSI

SN50V3-NB mod1

mod

Battery

RSSI

DS18B20 Temp

exit_state/input PA4

adc0

Temperature 

Humidity

 

 

SN50V3-NB mod2

mod

Battery

RSSI

DS18B20 Temp

exit_state/input PA4

adc0

distance

 

 

 

SN50V3-NB mod3

mod

Battery

RSSI

adc0

exit_state/input PA4

adc1

Temperature

Humidity

adc4

 

SN50V3-NB mod4

mod

Battery

RSSI

DS18B20 Temp

adc0

exit_state/input PA4

DS18B20 Temp2

DS18B20 Temp3

 

 

SN50V3-NB mod5

mod

Battery

RSSI

DS18B20 Temp

adc0

exit_state/input PA4

Weight

 

 

 

SN50V3-NB mod6

mod

Battery

RSSI

count

 

 

 

 

 

 

3.4 Datacake

Dragino NB-IoT sensors has its template in Datacake Platform. There are two version for NB Sensor,

As example for S31B-NB. there are two versions: S31B-NB-1D and S31B-NB-GE.

• S31B-NB-1D: This version have pre-configure DataCake connection. User just need to Power on this device, it will auto connect send data to DataCake Server.

• S31B-NB-GE: This verson doesn't have pre-configure Datacake connection. User need to enter the AT Commands to connect to Datacake. See below for instruction. 

3.4.1 For device Already has template

3.4.1.1 Create Device

Add Device in DataCake.

Choose the correct model from template.

Fill Device ID. The device ID needs to be filled in with IMEI, and a prefix of 'f' needs to be added.

3.4.2 For Device already registered in DataCake before shipped

3.4.2.1 Scan QR Code to get the device info

Users can use their phones or computers to scan QR codes to obtain device data information.

3.4.2.2 Claim Device to User Account

By Default, the device is registered in Dragino's DataCake Account. User can Claim it to his account.

3.4.3 Manual Add Decoder in DataCake ( don't use the template in DataCake)

Step1: Add a device

Step2: Choose your device type,please select dragino NB-IOT device

Step3: Choose to create a new device

Step4: Fill in the device ID of your NB device

Step5: Please select your device plan according to your needs and complete the creation of the device

Step6: Please add the decoder at the payload decoder of the device configuration. Decoder location: dragino-end-node-decoder/Datacake-Dragino_NB at main · dragino/dragino-end-node-decoder (github.com)

Due to version update, please use the following decoder for the new version firmware:
dragino-end-node-decoder/Datacake-Dragino_NB_New_Version at main · dragino/dragino-end-node-decoder (github.com)

Step7: Add the output of the decoder as a field

Step8: Customize the dashboard and use fields as parameters of the dashboard

3.4.4 For device have not configured to connect to DataCake

Use AT command for connecting to DataCake

AT+PRO=2,0

AT+SERVADDR=67.207.76.90,4445

3.5 Telemetry2U

Configuring the Dragino NB Sensor Settings

AT+SERVADDR=telemetry2u.com,4483 – Sets the server address and port for sending data to the Telemetry2U IoT platform.

AT+APN=simbase – Sets the APN required for LTE-M connectivity using a Simbase global SIM card.

ATZ– Reboots the device to apply the changes. It won’t transmit to Telemetry2U until added and configured on the platform.

AT+CFG – Displays the current configuration. Take note of the 8-byte (HEX) DEUI, which you’ll need in the next setup step.

And that’s it! These simple steps will get your device up and running on our Telemetry2U servers in no time.

Step 1: Log in Telemetry2U

Users can register a Telemetry2U account for their first use

https://telemetry2u.com/Identity/Account/Register Step 2: Add the device

**1. Select Network provide:**Users need to select Telemetry2U NB-IoT over UDP in order to connect to the platform

**2. Select device type:**Select the template you need to use

**3. Fill in Description:**Fill in the unique description

4. **Fill in IMEI:**The IMEI corresponds to the IME of the device

After completion, click "Greate"

Step 3: Check the data

For more information, please refer to the user manual on the Telemetry2U official website:

https://telemetry2u.com/Documentation/dragino-lte-m-nb-iot-sensors-iot-platform-integration

3.6 Node-Red (via MQTT)

3.6.1 Configure Node-Red

Take S31-NB UDP protocol as an example.

Dragino provides input flow examples for the sensors.

User can download the required JSON file through Dragino Node-RED input flow template.

Download sample JSON file link: https://www.dropbox.com/sh/mduw85jcuwsua22/AAAvwPhg9z6dLjJhmZjqBf_ma?dl=0

We can directly import the template.

The templates for S31-NB and NB95S31B are the same.

Please select the NB95S31B template.

Successfully imported template.

Users can set UDP port.

3.6.2 Simulate Connection

We have completed the configuration of UDP. We can try sending packets to node red.

3.6.3 Configure NB-IoT Sensors

• AT+PRO=3,0 or 3,5// hex format or json format
• AT+SUBTOPIC=<device name>or User Defined- AT+PUBTOPIC=<device name>or User Defined- AT+CLIENT=<device name> or User Defined- AT+UNAME=<device name> or User Defined- AT+PWD=“Your device token”

3.7 ThingsBoard.Cloud (via MQTT)

3.7.1 Configure ThingsBoard

3.7.1.1 Create Device

Create a New Device in ThingsBoard. Record Device Name which is used for MQTT connection.

3.7.1.2 Create Uplink & Downlink Converter

Uplink Converter

The purpose of the decoder function is to parse the incoming data and metadata to a format that ThingsBoard can consume. deviceName and deviceType are required, while attributes and telemetry are optional. Attributes and telemetry are flat key-value objects. Nested objects are not supported.

To create an uplink converter go to the Integrations center -> Data converters page and click “plus” button. Name it “MQTT Uplink Converter” and select type "Uplink". Use debug mode for now.

Downlink Converter

The Downlink converter transforming outgoing RPC message and then the Integration sends it to external MQTT broke

Note: Our device payload is already human readable data. Therefore, users do not need to write decoders. Simply create by default.

3.7.1.3 MQTT Integration Setup

Go to the Integrations center -> Integrations page and click “plus” icon to add a new integration. Name it “MQTT Integration”, select type MQTT;

• The next steps is to add the recently created uplink and downlink converters;

Add a topic filter:

Consistent with the theme of the node setting.

You can also select an MQTT QoS level. We use MQTT QoS level 0 (At most once) by default;

3.6.2 Simulate with MQTT.fx

3.7.3 Configure NB-IoT Sensor

AT Commands

• AT+PRO=3,3    // Use MQTT to connect to ThingsBoard. Payload Type set to 3.

• AT+SUBTOPIC=<device name>

• AT+PUBTOPIC=<device name>

• AT+CLIENT=<device name> or User Defined

• AT+UNAME=<device name> or User Defined

• AT+PWD=<device name> or User Defined Test Uplink by click the button for 1 second

3.8 ThingsBoard.Cloud (via COAP)

3.8.1 Configure ThingsBoard

3.8.1.1 Create Uplink & Downlink Converter

Uplink Converter

The purpose of the decoder function is to parse the incoming data and metadata to a format that ThingsBoard can consume. deviceName and deviceType are required, while attributes and telemetry are optional. Attributes and telemetry are flat key-value objects. Nested objects are not supported.

To create an uplink converter go to the Integrations center -> Data converters page and click “plus” button. Name it “COAP Uplink Converter” and select type "Uplink". Use debug mode for now.

Downlink Converter

The Downlink converter transforming outgoing RPC message and then the Integration sends it to external COAP broker.

3.8.1.2 COAP Integration Setup

Go to the Integrations center -> Integrations page and click “plus” icon to add a new integration. Name it “CoAP Integration”, select type COAP    ;

The next steps is to add the recently created uplink converters;

3.8.1.3 Add COAP Integration

3.8.2 Node Configuration(Example: Connecting to the Thingsboard platform)

3.8.2.1 Instruction Description

• AT+PRO=1,0(HEX format uplink)  &AT+PRO=1,5(JSONformat uplink)
• AT+SERVADDR=COAP Server Address,5683

Example: AT+SERVADDR=int.thingsboard.cloud,5683(The address is automatically generated when the COAP integration is created)

Note:The port for the COAP protocol has been fixed to 5683

• AT+URI1=11,character length,"Needs to be consistent with the CoAP endpoint URL in the platform",

-NB/NS products use the BC660K module, only need to configure only one URL command.

e.g. 

• AT+URI1=11,38, "i/faaa241f-af4a-b780-4468-c671bb574858" 

3.9 Tago.io (via MQTT)

3.9.1 Create device & Get Credentials

We use MQTT Connection to send data to Tago.io. We need to Create Device and Get MQTT Credentials first. 

Go to the Device section and create a device. Then, go to the section tokens and copy your device-token.

The device needs to enable the TLS mode and set the AT+TLSMOD=1,0 command.

On the Connection Profile window, set the following information:

• Profile Name: “Any name”

• Broker Address: mqtt.tago.io

• Broker Port: 8883

• Client ID: “Any value” On the section User credentials, set the following information:

• User Name: “Any value” // Tago validates your user by the token only

• Password: “Your device token”

• PUBTOPIC: “Any value”

• SUBTOPIC: “Any value” AT command:

• AT+PRO=3,0 or 3,5// hex format or json format

• AT+SUBTOPIC=<device name>or User Defined

• AT+PUBTOPIC=<device name>or User Defined

• AT+CLIENT=<device name> or User Defined

• AT+UNAME=<device name> or User Defined

• AT+PWD=“Your device token”

3.9.2 Simulate with MQTT.fx

Users can run the AT+PRO=3,5 command, and the payload will be converted to JSON format.

3.9.3 tago data

3.10 TCP Connection

AT command:

• AT+PRO=4,0     // Set to use TCP protocol to uplink(HEX format)

• AT+PRO=4,1     // Set to use TCP protocol to uplink(JSON format)

• AT+SERVADDR=120.24.4.116,5600    // to set TCP server address and port

Sensor Console Output when Uplink:

See result in TCP Server:

3.11 AWS Connection

Users can refer to Dragino NB device connection to AWS platform instructions

3.12 ThingsEye (via MQTT)

3.12.1 Configure ThingsEye

3.12.1.1 Create MQTT integration

Go to the Integrations center -> Integrations page and click “plus” icon to add a new integration. Name it “MQTT Integration_NB”, select type MQTT;

Next, directly select to create a new Uplink data converter and downlink data converter.

Add a topic filter:

Consistent with the theme of the node setting.

Note: Recommended MQTT broker: lns1.thingseye.io 8883, fixed use. Topic can be changed on their own, but it need to be consistent with the node's publish and subscribe topic.

You can also select an MQTT QoS level. We use MQTT QoS level 0 (At most once) by default;

3.12.1.2 Add credentials to the MQTT integration

Click on the MQTT integration you just created.

Click the edit icon in the upper right corner to enter the edit mode.

Add credential files.

Click this link to download the certificates.

When the addition is complete, save the Settings.

3.12.1.3 Setup uplink and downlink converters

First, you need to download the MQTT uplink/downlink JS code.

• Uplink Converter

The purpose of the decoder function is to parse the incoming data and metadata to a format that ThingsBoard can consume. 

Go to the Integrations center -> Data converters page, and find that MQTT uplink converter that was newly created when the integration was created.

Enter edit mode and apply MQTT uplink JS code to this uplink converter.

• Downlink Converter

Go to the Integrations center -> Data converters page, and find that MQTT downlink converter that was newly created when the integration was created.

Enter edit mode and apply MQTT downlink JS code to this downlink converter.

3.12.2 Simulate with MQTT.fx

3.12.3 Configure -NB node

First you need to configure the certificate to the -NB node. Follow the instructions in this link to configure the certificate.

Screenshot of successful certificate configuration:

• Configuring the CA Certificate

• Configure client certificate

• Configure client private key

When the certificate is configured, burn the boot program, burn the working firmware, and then restart the device.

Then configure the -NB node to connect to the ThingsEye platform:

AT Commands

• AT+PRO=3,5      // Use MQTT Connection & Json Payload
• AT+SERVADDR=lns1.thingseye.io,8883
• AT+SUBTOPIC=8899     // Consistent with the Topic of MQTT integration created by ThingsEye
• AT+PUBTOPIC=8899     // Consistent with the Topic of MQTT integration created by ThingsEye
• AT+CLIENT=NULL
• AT+UNAME=NULL
• AT+PWD=NULL
• AT+TLSMOD=1,2

Test Uplink by click the button for 1~3 seconds, the MQTT integration in ThingsEye allows you to view the data upstream from the device:

Go to "Device"  ->  "Search Device", enter the  IMEI of the device to find the device.

You can view the data that has just been uplink on the device:

3.12 ThingsEye (via UDP)

3.12.1 Configure ThingsEye

Note: 1. Since platform configuration involves port data forwarding, it will be handled by platform technicians. 2. Users only need to configure their NB devices and provide the NB device's “IMEI” to the platform technicians for port data forwarding to the corresponding user account.

3.12.2 Device Configuration

AT Commands

• AT+PRO=2,5      // Use UDP Connection & Json Payload
• AT+SERVADDR=server1.thingseye.io,11560     // Configure the UDP server domain name and port

Click the button for 1–3 seconds to test the uplink. ThingsEye's UDP integration feature allows you to view your device's upstream data.

Note: Requires enabling the Debug Receive Data function within the UDP integration feature, which is disabled by default.

Select the corresponding UDP integration -> Click to enter the UDP integration configuration interface -> Click the button in the upper-right corner to enter edit mode -> Click "Debug mode" -> Open "All messages (15 min)" -> Click "Apply" to save

:

Test Uplink by click the button for 1~3 seconds, the UDP integration in ThingsEye allows you to view the data upstream from the device:

Go to "Device"  ->  "Search Device", enter the  IMEI of the device to find the device.

You can view the data that has just been uplink on the device:

4. MQTT/UDP/TCP downlink

4.1 MQTT (via MQTT.fx)

Configure MQTT connections properly and send downlink commands to configure nodes through the Publish function of MQTT.fx_._

1. Configure node MQTT connection (via MQTT.fx):

AT command:

• AT+PRO=3,0 or 3,5// hex format or json format

• AT+SUBTOPIC=User Defined

• AT+PUBTOPIC=User Defined

• AT+UNAME=<device name> or User Defined

• AT+PWD=<device name> or User Defined

• AT+SERVADDR=8.217.91.207,1883    // to set MQTT server address and port

Note: To uplink and downlink via MQTT.fx, we need set the publish topic and subscribe topic different, for example: AT+SUBTOPIC=SE01\_SUB & AT+PUBTOPIC=SE01\_PUB.

2. When the node uplink packets, we can observe the data in MQTT.fx.

3. The downlink command can be successfully sent only when the downlink port is open.

    The downlink port is opened for about 3 seconds after uplink packets are sent.

    Therefore, when we see the node uplink packets in the Subscribe window, we need to immediately switch to the publish window to publish the hex format command.

Note: Users can edit the hex command in advance. When the node uplink, directly click the publish button several times to increase the success rate of command configuration.

5. FAQ

5.1 What is the usage of Multi Sampling and One Uplink?

The NB series has the feature for Multi Sampling and one uplink. See one of them

[http:///docs/wiki/nb-iot/rs485-sdi-12-sensor-nodes/sn50v3-nb/)

User can use this feature for below purpose:

1. Reduce power consumption. The NB-IoT transmit power is much more higher than the sensor sampling power. To save battery life, we can sampling often and send in one uplink.
2. Give more sampling data points.
3. Increase reliable in transmission. For example. If user set
   • AT+TR=1800        // The unit is seconds, and the default is to record data once every 1800 seconds (30 minutes, the minimum can be set to 180 seconds)
   • AT+NOUD=24     //  The device uploads 24 sets of recorded data by default. Up to 32 sets of record data can be uploaded.
   • AT+TDC=7200     //  Uplink every 2 hours.
   • this will mean each uplink will actually include the 6 uplink data (24 set data which cover 12 hours). So if device doesn't lost 6 continue data. There will not data lost.

5.2 Why the uplink JSON format is not standard?

The json format in uplink packet is not standard Json format. Below is the example. This is to make the payload as short as possible, due to NB-IoT transmit limition, a standard Json is not able to include 32 sets of sensors data with timestamp.

The firmware version released after 2024, Mar will use change back to use Json format. Detail please check changelog.

5.3 What is the data consumption for different transfer mode？

For the data consumption of NB-IoT End node in different transfer mode, reference link:

[https:///docs/wiki/Knowledge-Base/traffic-statistics-nbcb/)

5.4 How to Bypass the MCU and directly debug the Modem module

Module Interface

Use the GND, RX and TX pins of the USB-TTL connection module

Set the baud rate of the serial port tool to 115200, and the serial port tool will print out debug logs

6. Trouble Shooting:

6.1 Checklist for debuging Network Connection issue. Signal Strenght:99 issue.

There are many different providers provide NB-IoT service in the world. They might use different band, different APN & different operator configuration. Which makes connection to NB-IoT network is complicate.

If end device successfully attached NB-IoT Network, User can normally see the signal strengh as below (between 0~31)

If fail to attach network, it will shows signal 99. as below:

When see this issue, below are the checklist:

• Does your SIM card support NB-IoT network? If SIM card doesn't not specify support NB-IoT clearly, normally it doesn't support. You need to confirm with your operator.
• Do you configure the correct APN? Check here for APN settings.
• Do you lock the frequency band? This is the most case we see. Explain and Instruction.
• Check if the device is attached to Carrier network but reject. (need to check with operator).
• Check if the antenna is connected firmly.

If you have check all above and still fail. please send console log files (as many as possible) to support@dragino.com so we can check.

6.2 Issue: "NBIOT did not respond"

11:24:22.397 [44596]NBIOT did not respond.
11:24:24.315 [46530]NBIOT did not respond.
11:24:26.256 [48464]NBIOT did not respond.
11:24:28.196 [50398]NBIOT did not respond.
11:24:30.115 [52332]NBIOT did not respond.
11:24:32.127 [54266]NBIOT did not respond.
11:24:32.127 [54299]Restart the module...
11:24:39.181 [61332]No response when shutting down

This issue might due to initiate issue for NB-IoT module. In this case, please try:

1. Open Enclosure

2. Power off device by pull out the power on Jumper

3. Power on device by connect back the power jumper.

4. push reset button.

6.3 Issue: "Failed to readI MSI number"

[18170]Failed to read IMSI:1umber.
[20109]Failed to read IMSI numoer.
[22048]Failed to read IMSI number.
[29842lRestart the module...

Make sure that the SIM card is insert in correct direction and device is power off/on during insert. Here is reference link: Insert SIM Card.

6.4 Why sometime the AT Command is slow in reponse?

When the MCU is communicating with the NB-IoT module, the MCU response of AT Command will become slower, it might takes several seconds to response.

6.5 What is the Downlink Command Format for NB Devices?

We strongly recommend that users upgrade their -NB device firmware to the latest protocol stack version (D-BC660K-005 or later).

The latest firmware introduces a unified downlink command format which simplifies device configuration and ensures compatibility across different platforms.

For all details regarding the new standard format, please refer to: 7.2.7 Standard JSON Downlink Format

6.6 How to get the debug log for further analyze?

If user is not able to solve the connection issue, user can use below method and get the device log and send to Dragino (Support@dragino.cc) for further analyze.

Step1: Use Mobile Phone to connect device

See this link: how to connect via Mobile Phone:

Step2: Get Log by different commands.

Use below three method to generate logs.

• AT+CFG       --> Command to show the current configuration- AT +GETLOG   --> Command to get the previous upstream log
• press the toggle button for 1 ~2 seconds     --> Trigger a uplink

Above are the output example for about three action:

Step3: Export Log

select the log you want to export, then click the share icon on the far right to enter the document that comes with your phone and choose to export it.

6.7 How to find the AT Command Password if lost?

Why can't the password access AT command after upgrade(-NB)?

Because the new version of -NB firmware has updated the factory reset function, users can choose to restore all parameters to factory Settings, or keep the password to restore the rest of the parameters to factory Settings.

This update changes the password address of the firmware, so the password will be invalid after the customer upgrades from the old version of firmware (without FDR1 function) to the new version of firmware (with FDR1 function).

Two different restore factory Settings configurations.

AT command:

• AT+FDR        // Reset Parameters to Factory Default.
• AT+FDR1     // Reset parameters to factory default values except for passwords.(new)

Version Confirmation

We are now dividing the old firmware(without FDR1 function) with the new firmware(with FDR1 function) by whether it contains FDR1 functionality. Please refer to the table:

General Model Firmware version (without FDR1 function) Firmware version (with FDR1 function)

CPL03-NB, S31-NB, SN50V3-NB, TS01-NB, D20-NB, DS03A-NB, DDS04-NB, DDS45-NB, DDS20-NB, DDS75-NB, LDS12-NB, LDS40-NB, LMS01-NB, MDS120-NB,  MDS200-NB, SE01-NB, SPH01-NB;

Before V1.2.1

After V1.2.1 (including V1.2.1)

WL03A-NB, SDI-12-NB;

Before V1.0.2

After V1.0.8 (including V1.0.2)

SW3L-NB, PS-NB;

Before V1.0.5

After V1.0.5 (including V1.0.5)

RS485-NB

Before V1.0.8

After V1.0.8 (including V1.0.8)

UART connection and firmware update methods

Users can query passwords only using the UART interface via the STM32CubeProgrammer.

See UART Connection.

update firmware through UART TTL interface : Instruction.

query the password via STM32CubeProgrammer

Users can use the password address to query the password through STM32CubeProgrammer.

• The password address for old firmware(without FDR1 function) : 0x08019000

• The password address for new firmware(with FDR1 function) : 0x08025D00 Notice: The password can only be queried after the firmware is run once. Procedure for querying the password(old firmware):

• After the firmware upgrade is complete, switch back to the FLASH and reset the node to run the firmware once.

• Then place the switch at the ISP and connect to the STM32CubeProgrammer (same as when burning the firmware).

• Click "Device memory", enter 0x08019000 in "Address", and click "Read"

• Find the 0x08019000 address field and then read the current password as shown in the screenshot below.

Missing source image in original Wiki export: image-20240827171901-3.png

Procedure for querying the password(new firmware):

Refer to the old and new firmware division above, and run the firmware first after updating the firmware.

• After the firmware upgrade is complete, switch back to the FLASH and reset the node to run the new firmware once.
• Then place the switch at the ISP and connect to the STM32CubeProgrammer (same as when burning the firmware).
• Click "Device memory", enter 0x08025D00 in "Address", and click "Read"
• Find the 0x08025D00 address field and then read the current password as shown in the screenshot below.

Missing source image in original Wiki export: image-20240827180414-1.png

Special case

If the user has never changed the password manually, the user cannot find the valid password through the above two password addresses. In this case, the valid password is still the original password on the node box label (AT+PIN).

Invalid query screenshot example:

Missing source image in original Wiki export: image-20240827181447-4.png

Missing source image in original Wiki export: image-20240827181431-3.png

7. NB-IoT Stack Changelog (BC660K)

This chapter documents the evolution of the NB-IoT protocol stack used in Dragino -NB and -NS series devices. These stack updates are common across all compatible models.

7.1 004 Protocol Stack Update Content

7.1.1 Network access display

Feature: When the device successfully joins the network, it will print Network Information in the startup log.

Device response format: Network Information:"RSSI","SINR","BAND"

Example:

Network Information:"RSSI:-63","SINR:8","BAND:8"

7.1.2 Format AT+SERVADDRcommand

Feature: Automatically delete spaces entered during configuration to prevent users from entering the wrong address.

Example: 

Send command: AT+SERVADDR=broker. hivemq. com,1883

During the writing process, extra spaces in the command will be removed before writing to the device.

as follows:

AT+SERVADDR=broker.hivemq.com,1883

7.1.3 Downlink Platform -- TE

Feature: Support for UDP downlink on the TE platform, with the addition of the command AT+DOWNTE

AT command: AT+DOWNTE Command Example Function/Parameters Response/Explanation

AT+DOWNTE=? Get current Settings

0,0   (default)
OK

AT+DOWNTE=a,b a: Set the conversion between the downlink of the standard version and 1T version

0: Set the downlink of the standard version.
1: Set the downlink of the 1T version(ThingsEye platform) 

b: Enable/Disable downlink debugging

0: Disable downlink debugging mode.
1: Enable downlink debugging mode, users can see the original downlink reception.

Example:

• AT+DOWNTE=0,1  // Set to standard version downlink, and enable downlink debugging.
• AT+DOWNTE=1,1  // Set to 1T version downlink, and enable downlink debugging.

Downlink Command:  

No downlink commands for feature

7.1.4 Domain name resolution

Feature: The domain name resolution mechanism has been updated, the AT+DNSTIMEcommand has been removed, and the AT+BKDNScommand has been added.

AT command: AT+BKDNS Command Example Function/Parameters Response/Explanation

AT+BKDNS=? Get current Settings

1,0,NULL  (default)
OK

AT+BKDNS=a,b,c a: Enable/Disable dynamic domain name resolution.

1: Disable dynamic domain name update. The ip address will be saved after the domain name is resolved, if the next domain name resolution fails, the last saved ip address will be used.
2: Enable dynamic domain name update. The ip address will be saved after domain name resolution, if the next domain name resolution fails, the last saved ip address will be used, and the domain name resolution will be updated regularly according to the time set by the customer.

b: Set the time to update the domain name resolution at regular intervals.

Unit: hour

c: Set the IP address manually.

The format is the same as AT+SERVADDR
If domain name resolution fails, this ip address will be used directly, if domain name resolution succeeds, parameter c will be updated to the successfully resolved IP address.

Example:

• AT+BKDNS=1,0        // Dynamic domain name resolution is disabled.
• AT+BKDNS=2,1        // The dynamic domain name resolution function is enabled and the automatic update time is set to 1 hour.
• AT+BKDNS=2,4,3.69.98.183,1883      // The dynamic domain name resolution function is enabled and the automatic update time is set to 4 hour, and manually set the ip address, if the domain name failed to resolve, it will directly use this ip to communicate. When the next domain name resolution is successful, it will be updated to the ip address of the successful resolution.

Downlink Command:  

No downlink commands for feature

7.1.5 Preventing unexpected restarts

Features: The device enters sleep mode by pressing the button five times consecutively after leaving the factory. To prevent accidental crashes or resets, a deep sleep flag is programmed. If the device is unexpectedly reset and restarted, it will re-enter deep sleep mode. A hardware reset will also put it into deep sleep mode.

Exit sleep mode: The only way is to send a reset command via serial port or press and hold the ACT button for 5 seconds to reset the device software.

7.1.6 System crash detection

Features: The device checks the NB module every hour to determine if it has crashed, and it also checks during deep sleep.

7.1.7 DNSCFG command removes format restrictions

Features: The AT+DNSCFGcommand has been expanded from 19 characters to 40 characters, removing format restrictions.

7.1.8 Add IMSI

Feature: Adds an IMSI field to the upstream payload.

7.1.9 Increase current time

Feature: The current sampling time is added to the current data payload in the JSON uplink format.

7.2 005 Protocol Stack Update Content

7.2.1 Get stack version downlink

Notice: This command is only valid for JSON uplink format.

Feature: You can easily identify the NB-IoT protocol stack version on your device by sending the following JSON-formatted command through the device's connection platform:

Taking the MQTT protocol as an example:

Platform downlink command ** : Event:status

After receiving the downlink data, the device will perform another uplink query to check the device version after the current data packet has been sent, as shown in the figure below:

Device response format:

{"IMEI":"863663069842558","Image Version":"v1.4.0","NB-IoT Stack":"D-BC660K-005","Model":"S31x-NB"}

7.2.2 Configure an NTP server

Feature: This command can change the NTP server to a local NTP server, thereby obtaining the local time for time synchronization.

Notice:

• When the SIM card cannot synchronize its time with the default NTP server, it will automatically synchronize with the NTP server configured using this command.

AT command:

• AT+NTP="s1a.time.edu.cn"      // Configure the time synchronization server as s1a.time.edu.cn Downlink command: Notice: This command is only valid for JSON uplink format.

• AT Format: {"Config":"[AT+NTP="s1a.time.edu.cn"\"}

7.2.3 Specify a SIM carrier

Feature: This feature automatically configures the carrier each time a packet is sent, preventing the device from being unable to find a signal and thus being unable to send packets due to the loss of the operator code.

AT command:

• AT+QCOPS=46000       // Configure the carrier code to China Mobile's MCC and MNC.

Downlink command: Notice: This command is only valid for JSON uplink format.

• Downlink Format: {"Config":"[AT+QCOPS=46000\"}

7.2.4  Increase stack size

Feature: In complex task scenarios, the device will not reset or malfunction due to stack overflow.

For example:

quickly and continuously execute multiple AT commands: configuration, query, fast uplink transmission, etc.

7.2.5 Fixed signal over-limit bug

Feature:  During communication (such as before data upload), the device can correctly acquire and report the signal strength, and the reported CSQ value is within a reasonable defined range.

7.2.6 Automatic reset function

Feature: The device will automatically perform a software reset function when it continuously detects no signal (Signal Strength: 99) for 12 consecutive TDC cycles.

7.2.7 Standard JSON Downlink Format

Features: Unified JSON downlink format across all NB-IoT products for consistent command delivery.

7.2.7.1  JSON Downlink Format Specification

{"Config":"[ATcommand1;ATcommand2;...ATcommandX]"}

• Config: Fixed key indicating a configuration command sequence.
• Value: A string containing AT commands separated by semicolons (;) within square brackets.

Examples:

① Basic Configuration

For settings that take effect immediately (e.g., updating reporting intervals): {"Config":"[AT+TDC=360;AT+CSQTIME=5\]"

// This sets the periodic uplink interval (AT+TDC) to 360 seconds and the signal search attempt duration (AT+CSQTIME) to 5 minutes.

② Configuration Requiring Device Reset

For commands that require a device restart to apply (e.g., changing the server address or protocol), you must append the reset command ATZat the end:
{"Config":"[AT+SERVADDR=xxx.xxx.xxx.xxx,yyyy;ATZ\]" {"Config":"[AT+PRO=2,0;ATZ\]"

//The ATZcommand ensures the device reboots and the new settings take effect.

7.2.7.2 Important Notes on HEX Command Format

①  Standard HEX Downlink

When sending individual AT commands in their HEX-encoded format (as defined in the command reference), send them directly as a single HEX string.

Example:

AT+TDC=300corresponds to 0100012C           Send: 0100012C

② Special Case for ThingsBoard Platform

To enable HEX-format downlink commands on the ThingsBoard platform (AT+PRO=2,3), you must configure AT+DWONTE=1,1.When this configuration is active, any HEX-format downlink command must be wrapped in curly braces {}.

Example: To send the HEX command 0100012C in this mode, the downlink format must be: {0100012C}

//This ensures proper parsing by the ThingsBoard platform and the device's firmware.

7.2.8 ACK and data retransmission:

Note：The SN5OV3-NB, WSQ-NB, WSC2-N and WSC2-COMPASCT-NS products do not include this function.

Function: The datalog function for MQTT, TCP, and UDP protocols determines whether a signal or received ACK warrants a retransmission.

New command: AT+REDPT

When AT+REDPT=1,and the device does not receive an ACK response from the server, the device will automatically retransmit the data packet for which no ACK was received when it subsequently receives an ACK.

Note: 1. The retransmitted upstream format is the same as the datalog format; both are HEX format upstream. 2. If the UDP server the user is connected to does not have automatic downlink ACK functionality, the server will receive an automatic downlink ACK confirmation when an uplink packet is received. The downlink command format is: Confirm=200. (Confirm=200 is only visible when downlink debugging is enabled, i.e., AT+DOWNTE=0,1) 3. The Confirm=200 command only applies to the UDP protocol and is invalid for MQTT and TCP protocols. 4. When Confirm=200 is sent downlink simultaneously with other commands, the user needs to ensure that Confirm=200 is sent downlink first.

7.2.9 Json Format Downlink ACK feedback

Function: After the device successfully executes a downlink command in JSON transmission mode, this function will automatically send an ACK confirmation data packet containing the device's IMEI to the platform. As long as a reply is uploaded, the device has definitely received and processed the downlink command.

Note: 1. This feature is only available in JSON transport mode. 2. UDP servers do not automatically send downlink ACKs because the UDP protocol specification does not define ACK. Whether or not acknowledgment is required is added by the application developer; the device command specification is: Confirm=200. This command only applies to the UDP protocol.

Triggering requirement:

Any command in JSON format sent from the platform.

Device response format:

{"IMEI":"863663069842558","Downklink_Ack":"success"}

7.3 006 Protocol Stack Update Content

7.3.1 Over-the-Air (OTA) Firmware Update

Feature: Added support for Over-the-Air (OTA) firmware updates. Devices with external SPI Flash can now receive firmware updates remotely without physical access.

Implementation: OTA functionality is triggered via downlink command F9 01 or AT command AT+UPGRADE.

Related Documentation: For detailed OTA setup and usage instructions, refer to: OTA Update Firmware for NB-IoT/LTE-M End Nodes

7.3.2 TLS Certificate Write Function

Feature: Added support for writing TLS certificates directly using the device firmware. Previously, writing TLS certificates required a dedicated firmware tool (a special program for certificate writing). Now, certificates can be configured directly using standard AT commands within the working firmware.

Related Documentation: For detailed certificate writing instructions, refer to: TLS Certificate Configuration Guide

7.3.3 Serial Log Upload (GETLOG)

Feature: Added AT+GETLOG=1 command and corresponding downlink command F8 01 to upload saved serial port logs to the server.

Command Type

Command

Behavior

AT Command

AT+GETLOG=1 Device will upload saved serial logs after the next data packet

JSON Downlink

{"Config":"[AT+GETLOG=1\]"} Device immediately uploads saved serial logs

HEX Downlink

F8 01

Device immediately uploads saved serial logs

7.3.4 MQTT QoS Level Default Change

Feature: Changed default MQTT QoS (Quality of Service) level from 2 to 0.

Command: AT+MQOS

Setting

Description

AT+MQOS=0(default)

QoS 0 - At most once delivery (no acknowledgment)

AT+MQOS=1 QoS 1 - At least once delivery (acknowledgment required)

AT+MQOS=2 QoS 2 - Exactly once delivery (highest reliability, higher power consumption)

Impact: This change reduces network traffic and improves power efficiency for standard sensor data transmission. For applications requiring guaranteed delivery, users can set AT+MQOS=1or AT+MQOS=2.

7.3.5 DNS Resolution Optimization

Feature: Optimized DNS domain name resolution mechanism to improve reliability and prevent resolution failures.

Details: Internal improvements to the DNS resolution process reduce the likelihood of resolution errors, ensuring more stable connectivity when using domain names for server addresses.

Related Command: AT+BKDNS (enhanced for better error handling)

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