Ebyte NB124E User manual

Copyright ©2012–2023，Chengdu Ebyte Electronic Technology Co.,Ltd
NB124
Dual serial port server User Manual
NB124E
Dual Serial Port Server User Manual

Chengdu Ebyte Electronic Technology Co.,Ltd NB124E_User Manual
Copyright ©2012–2023，Chengdu Ebyte Electronic Technology Co.,Ltd
Content
Chapter 1 Product Introduction ................................................................................................................................... 1
1.1 Functions and Features .........................................................................................................................................1
Chapter 2 Quick Start .................................................................................................................................................. 3
2.1 Hardware preparation ........................................................................................................................................... 3
2.2 Software Preparation ............................................................................................................................................ 3
2.3 Device default parameter test steps ......................................................................................................................4
2.3.1 Hardware connection .................................................................................................................................4
2.3.2 Device parameter configuration ................................................................................................................4
2.3.3 Turn off the computer firewall .................................................................................................................. 5
2.3.4 Open “serial port assist” ............................................................................................................................6
2.3.5 Open Net assist ..........................................................................................................................................6
2.3.6 TX, RX data Test .......................................................................................................................................7
Chapter 3 Product Review ..............................................................................................................................................8
3.1 Technical Parameters ............................................................................................................................................8
3.2 Interface description ............................................................................................................................................. 9
3.3 Indicator light description .................................................................................................................................. 10
3.4 Size ..................................................................................................................................................................... 12
Chapter 4 Basic functions ..........................................................................................................................................13
4.1 Correspondence between channel and serial port ..............................................................................................13
4.2 Local network parameters ............................................................................................................................... 13
4.2.1 Local IP ................................................................................................................................................... 13
4.2.2 DNS (domain name resolution) .............................................................................................................. 13
4.2.3 Reconnection cycle for Network disconnection ..................................................................................... 13
4.2.4 Timeout restart (restart without data) ......................................................................................................14
4.3 Hardware reset to factory ................................................................................................................................... 14
4.4 Device working mode ........................................................................................................................................ 14
4.4.1 TCP Server .............................................................................................................................................. 14
4.4.2 TCP Client ............................................................................................................................................... 15
4.4.3 UDP Server ..............................................................................................................................................15
4.4.4 UDP Client .............................................................................................................................................. 15
4.4.5 HTTP client ............................................................................................................................................. 16
4.5.6 MQTT client ............................................................................................................................................18
4.6 Channel port ....................................................................................................................................................... 21
Chapter 5 Advanced Features ....................................................................................................................................22
5.1 Heartbeat package and registration package ......................................................................................................22
5.1.1 Heartbeat package ................................................................................................................................... 22
5.1.2 Registration package ....................................................................................................................................... 22
5.2 Short connection ..............................................................................................................................................23
5.3 Serial buffer cleaning ......................................................................................................................................... 23
5.4 Modbus gateway .................................................................................................................................................24
5.4.1 Simple Protocol Conversion ................................................................................................................... 24
5.4.2 Multi-host mode ...................................................................................................................................... 26

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5.4.3 Storage gateway ...................................................................................................................................... 27
5.4.4 Configurable Gateway ..........................................................................................................................28
5.4.5 Automatically upload .............................................................................................................................. 30
5.5 Firmware upgrade ............................................................................................................................................31
5.5.1 UDP upgrade ........................................................................................................................................... 31
5.5.2 Serial upgrade ..........................................................................................................................................33
Revision History ...........................................................................................................................................................35
About Us .......................................................................................................................................................................35

Chengdu Ebyte Electronic Technology Co.,Ltd NB124E_User Manual
Copyright ©2012–2023，Chengdu Ebyte Electronic Technology Co.,Ltd
Chapter 1 Product Introduction
NB124E is a 2-way serial port server that supports POE power supply. It integrates the TCP/IP protocol stack
inside, which can realize data transparent transmission from the 2-way serial port to the Ethernet port. The device
has the function of ModBus gateway, supports Modbus TCP to RTU, and supports automatic polling. The product
adopts industrial-grade standard design to ensure the stability of the equipment in harsh working environments, and
the rich indicator lights are used to feedback the different working states of the equipment.
1.1 Functions and Features
Stable and reliable industrial design, high-level port protection;
Abundant LED status indicators to quickly locate the working status of the device;
Support POE power supply;
Support Phoenix terminal or DC power supply, DC 8-28V wide voltage input, support reverse connection
protection;
Support terminal interface (RS485/RS422) and standard DB9 interface (RS232);
The baud rate supports 2400~115200bps, and supports multiple verification methods;
Support multiple registration packets and heartbeat packet sending, such as connection sending MAC,
connection sending customization, etc.;
Supports stable and reliable host computer and AT command configuration, independent configuration of four
channels does not affect each other;
Support DNS domain name resolution, domain name resolution server can be configured;
Support DHCP to dynamically obtain IP, subnet mask, default gateway, DNS server address;
Support multiple working modes TCP client, TCP server, UDP client, UDP server, MQTT client, HTTP client;
The 2-way server mode can be turned on at the same time, supporting 14 clients to dynamically allocate and
access, and a single server supports 15 clients to access;
Support UDP server mode with memory mode, records the UDP address of the last communication, and uses it
as the destination address of the next communication;
Support a variety of Modbus gateways, which can realize the active reporting of RTU devices, support the
mutual conversion of Modbus TCP and Modbus RTU protocols, and can be configured as a storage mode to
automatically collect device data, or use a multi-host mode with one question and one answer;
Support MQTT gateway function, fast access to Alibaba Cloud and standard MQTT3.1.1 servers (OneNET,
Baidu Cloud, Huawei Cloud, etc.);
Support Modbus data to actively report to TCP transparent transmission server, MQTT server and other
servers;
Support HTTP client mode, use HTTP/1.1 protocol, can be configured as GET, POST two request methods;
Support TCP/IP direct communication or connect communication through "virtual serial port";
Abundant independent LED status indicators, supporting links, network cables, data sending and receiving,
etc.;
Support the host computer to perform firmware upgrade or firmware switch through UDP or serial port;

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The isolation version supports independent hardware isolation of 2 RS485 serial ports.

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Chapter 2 Quick Start
2.1 Hardware preparation
One laptop with RJ45 network port;
One NB124E serial port server;
One DC12V 1A power adapter (not necessary if there is a POE switch);
A network cable;
One USB to RS485 serial cable;
As is shown in the following figure:
Laptop
Network Cable
NB124E
DC 12V1A
USB to RS485 converter
wires
【Note】Only use one RS485 interface for demonstration, and please use the corresponding USB converter for
other interfaces;
2.2 Software Preparation
Serial port debugging assistant (XCOM), network debugging assistant (TCP/IP debugging assistant), Ebyte
network configuration tool (configuration host computer), official website address: www.cdebyte.com, product

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details provide a download interface.
Network Assistant
XCOM
Ebyte network configuration tool
【Note】The serial port assistant software may be different from that provided on the official website, please refer
to the similar one.
2.3 Device default parameter test steps
Different channels use the same IP but different local ports. For example, the factory-configured channel 1
corresponds to port 8001, and channel 2 corresponds to port 8002. For details, see the chapter "Correspondence
Between Channels and Serial Ports".
2.3.1 Hardware connection
1. Connect the serial port server network port and the computer network port with a network cable;
2. Use a USB to RS485 serial cable to connect the USB port of the computer to any RS485 port of the serial server;
3. Use the power adapter (DC 8-28V) to power on the device, and observe whether the indicator light is normal,
refer to "indicator light description";
4. After confirming that there is no problem with the status, proceed to the next step of configuration;
2.3.2 Device parameter configuration
In order to let users have a simple understanding of the serial server, we use the default parameters of the serial
server to conduct data transparent transmission tests. The default parameters of NB124E serial server device are
shown in the table below.

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Item no.
Default parameters
IP address
192.168.3.7
Subnet mask
255.255.255.0
gateway
192.168.3.1
Channel 1 working mode
TCP_SERVER
Channel 1 local port
8001
Serial port baud rate
115200
Serial port parameters
NONE/8/1/NONE
Make sure that the computer IP and serial server IP are in the same network segment and cannot conflict.
The inspection method is shown in the figure below:
2.3.3 Turn off the computer firewall
If the communication is unsuccessful, the user can try to turn off the firewall on the computer and try again.

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2.3.4 Open “serial port assist”
Choose correct COM number, configure correct serial port parameters（115200-8N1），open the serial port,
as shown in the below：
2.3.5 Open Net assist
Choose“TCP Client”，set remote IP as“192.168.3.7”，set remote port as“8001”as shown in below：

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2.3.6 TX, RX data Test
Click the 【send】botton on the “Net assist”and “Serial port asssit” respectively，it can do transparent transmission
between net and serial port successfully, as shown in the below picture:

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Chapter 3 Product Review
3.1 Technical Parameters
Item
Port
Instructions
Power supply
Crimp terminal
DC 8～28 power supply；
Crimp terminal: 5.08mm Phoenix terminal
DC female head: straight plug-in round hole, OD
5.5mm, ID 2.0mm;
DC female head
Network Port
RJ45
10M，POE version support POE power supply
Serial Port
Channel 1～
Channel 2
Port 1（RS485，3.81mm Phoenix terminal）；
Port 2（RS232，standard RS232, DB9 female head）；
Port 3（RS422，3.81mm Phoenix terminal）；
Working Mode
TCP Server（default）、TCP Client、UDP Server、UDP Client、HTTP Client、
MQTT Client
Network
Protocol
TCP/IP、UDP、MQTT、HTTP、IPv4、ICMP、APR、DHCP、DNS
IP acquisition
method
DHCP、State IP（default）
DNS
support，address configurable
Configure
Method
Parameter configuration host computer, AT command
IP address
192.168.3.7（customizable）
Local port
Channel 1～2：8001-8002（customizable）
Subnet mask
255.255.255.0（customizable）
Gateway
192.168.3.1（customizable）
Serial cache
512 Byte
Serial
packaging
mechanism
512 Byte
Serial baud rate
2400 ～115200 bps（default 115200）
Data bit
8
Stop bit
1（default）、2
Parity bit
None（default）、Odd、Even
Installation
Positioning hole
Product size
173 x 95x26.5mm （LxWxH）
Product weight
360g ± 5g
Working
temperature and
humidity
-40 ～+85℃、5% ～95%RH（no condensation）

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Storage
temperature and
humidity
-40 ～+105℃、5% ～95%RH（no condensation）
3.2 Interface description
序号
名称
功能
说明
1
RS232-2
Serial port 2-RS232
Standard DB9 female head，2-TXD、3-RXD、
5-GND
2
RS232-1
Serial port 1-RS232
Standard DB9 female head，2-TXD、3-RXD、
5-GND
3
RS422-1-R+
Serial port 1-RS422 -R+
3.81mm Phoenix terminal
4
RS422-1-R-
Serial port 1-RS422 -R-
3.81mm Phoenix terminal
5
GND
Serial port 1 Ground
3.81mm Phoenix terminal

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6
RS422-1-T+/A
Serial port 1-RS422 -T+
Serial port 1-RS485 A
3.81mm Phoenix terminal
7
RS422-1-T-/B
Serial port 1-RS422 -T-
Serial port 1-RS485 B
3.81mm Phoenix terminal
8
RS422-2-R+
Serial port 2-RS422 -R+
3.81mm Phoenix terminal
9
RS422-2-R-
Serial port 2-RS422 -R-
3.81mm Phoenix terminal
10
GND
Serial port 2 Ground
3.81mm Phoenix terminal
11
RS422-2-T+/A
Serial port 2-RS422 -T+
Serial port 2-RS485 A
3.81mm Phoenix terminal
12
RS422-2-T-/B
Serial port 2-RS422 -T-
Serial port 2-RS485 B
3.81mm Phoenix terminal
13
-
DC 8-28 V Negative pole
DC 8-28 V，5.08mm Phoenix terminal；
14
+
DC 8-28 V Positive pole
DC 8-28 V，5.08mm Phoenix terminal；
15
DC-IN
DC power input
DC 8-28 V；
OD 5.5mm，ID 2.0mm straight plug-in round
hole；
16
Ethernet
Ethernet interface
Standard RJ45 Ethernet interface
17
Reload
factory reset button
After long pressing for 5s, NET led is always
on for 5s, and the device restores to factory
settings
Note：Phoenix terminal cannot supply power with the DC plug at the same time.
3.3 Indicator light description
Label
Function
Instructions
POWER
Power indicator
Connect to the power supply, light up;
NET
Running lights
Disconnected: 100ms on and 900ms off, flashing
periodically;
Connected：flashing in 1s cycle;
LINK1
Channel 1 Status
Indicator
No link connection: the indicator light is off;
With link connection: the indicator light is always on;
UDP mode: the indicator light is always on;

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DATA1
Channel 1 data
indicator
Data sending and receiving: flashes when the network or
serial port sends and receives data;
LINK2
Channel 2 Status
Indicator
No link connection: the indicator light is off;
With link connection: the indicator light is always on;
UDP mode: the indicator light is always on;
DATA2
Channel 2 data
indicator
Data sending and receiving: flashes when the network or
serial port sends and receives data;
【Note】Status of some special working mode indicator lights:
1、Restore the factory, NET is always on for 5s, and the other indicators remain on and will go out until NET
goes out;
2、Wait for the firmware burning, except for the power indicator light, the other indicators will blink at a
cycle of 50ms until the upgrade file is transferred, or exit the firmware burning waits;
3、During the firmware burning operation, the indicator lights except the power indicator will flash at a cycle
of 500ms until the upgrade is completed;

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3.4 Size

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Chapter 4 Basic functions
4.1 Correspondence between channel and serial port
Baud rate：2400、4800、9600、14400、19200、38400、57600、76800、115200bps；
Data bit：Only supports 8 bits；
Parity bit: support no parity (NONE), odd parity (ODD), even parity (EVEN);
Hardware flow control: not supported;
Channel
Serial Port
Indicator
Serial protocol
Factory port, mode
Channel 1
COM1
PORT1
RS485、RS232、RS422
8001、TCPS
Channel 2
COM2
PORT2
RS485、RS232、RS422
8002、TCPS
4.2 Local network parameters
4.2.1 Local IP
STATIC（Static IP）：Users can define and configure IP, subnet mask, default gateway, domain
name resolution server (DNS server);
DHCP (dynamic IP acquisition): The device logs in to the server to automatically obtain the IP
address, subnet mask, gateway address, and DNS server address;
4.2.2 DNS (domain name resolution)
When the user enters the domain name, the DNS server will be automatically queried, and the
DNS server will retrieve the database to obtain the corresponding IP address. In the static IP mode,
the user can customize the domain name resolution server to resolve private domain name server
data. In the dynamic IP mode The device automatically follows the domain name resolution server
configured by the routing device, and the user only needs to modify the DNS server of the routing
device, no need to configure the device.
4.2.3 Reconnection cycle for Network disconnection
When the device detects that it is disconnected from the server, it periodically initiates a

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reconnection request. Therefore, the "disconnection reconnection time" will not affect the connection
establishment time under normal circumstances. The user can customize the reconnection request
period, and the default is 5s.
4.2.4 Timeout restart (restart without data)
The device monitors data sending and receiving. If the device does not send and receive data for
a long time, the device will automatically restart to ensure the stability of long-term work.
The default cycle of this function is 30 minutes, and the user can customize the cycle of
restarting with timeout or no data.
4.3 Hardware reset to factory
Keep pressing the Reload pin of the device for 5s until the NET indicator stops flashing, keep
the NET indicator on for 5s, and the device is restored to factory.
4.4 Device working mode
4.4.1 TCP Server
In the TCP Server mode, the device listens to the local port, accepts the connection request from
the client and establishes a connection for data communication. When the Modbus gateway function
is turned off, the device sends the data received by the serial port to all client devices connected to
the device.
The number of clients that can be accessed by the server is dynamically adjusted. First, ensure
that each channel of the 2 channels can establish a complete communication link. In addition, the
device also has 14 dynamic access communication links. For example, if the device turns on the
2-channel server mode, each The server can access 8 client devices, or if the device opens 1 server,
the server can connect to 15 client devices. If the number of client devices exceeds the access
number, the device will refuse to connect.

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4.4.2 TCP Client
When the device is working, it will actively initiate a connection request to the server and
establish a connection to realize the interaction between serial port data and server data.
To use the client, you need to configure the IP address/domain name and target port of the target
accurately.
The two channels can independently open 2-way TCP clients.
4.4.3 UDP Server
UDP Server means that the device does not verify the source IP address of the data when using
the UDP protocol to communicate. After receiving a UDP data packet, it saves the source IP address
and source port of the data packet, and sets it as the target IP and port, so The data sent by the device
only sends data packets to the source IP address and port where the device received the data last
time.
This mode is usually used in scenarios where multiple network devices communicate with this
device, and the frequency is high, and the TCP Server cannot meet the conditions.
Using UDP Server requires the remote UDP device to send data first, otherwise the data cannot
be sent normally.
【Note】In UDP mode, the data sent by the network to the device should be less than 512Bit per packet, otherwise
it will cause data loss.
4.4.4 UDP Client
UDP Client is a connectionless transmission protocol that provides transaction-oriented simple
and unreliable information transmission services. There is no connection establishment and
disconnection, and data can be sent to the other party only by configuring the destination IP and
destination port. It is usually used in data transmission scenarios where there is no requirement for
the packet loss rate, the data packets are small and the sending frequency is fast, and the data is to be
transmitted to the specified IP.
In UDP Client mode, the device will only communicate with the configured (target IP and target
port) remote UDP device.
In this mode, the destination address is set to 255.255.255.255, and the sending data will be

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broadcast on the entire network segment, but the sending and receiving devices need to ensure that
the ports are consistent, and ensure the device can also receive broadcast data.
【Note】In UDP mode, the data sent by the network to the device should be less than 512Bit per packet, otherwise
it will cause data loss.
4.4.5 HTTP client
This mode can realize HTTP automatic package function, and provides two methods of GET and POST.
Customers can configure URL, Header and other parameters by themselves, and the device will send the package to
realize fast communication between serial port data and HTTP server. URL and Header are the most The length
supports 128 bytes of data, and the two channels can independently open the HTTP client mode without affecting
each other.
The HTTP request data should be smaller than the packet length (512 bytes), otherwise the device will divide
the request data into multiple packets for request, resulting in abnormal request.
It supports configuring whether to return the HTTP protocol header, and the returned data is shown in the
figure below:

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Configuration instructions: Turn on the upper computer, search for the device and enter the device configuration
interface, configure the "network parameters" first, it is recommended to use the DHCP function to avoid incorrect
configurations that cause device IP exceptions (network segment errors, IP conflicts, etc.), and then configure the
channel using the HTTP function, support 2 channels to configure HTTP client mode at the same time, here is an
example to explain by GET requesting "Baidu" webpage (URL: empty, HEADER: Host: www.baidu.com, target
domain name: www.baidu.com, target port: 80 , the local port is recommended to use a random port), the specific
configuration is shown in the figure below:
The request data is "/", use the serial port assistant to get the web page: