Communication port

A communication port is a physical input/output interface that sends and receives data between devices. "Communication port" is a generic term that describes a plug port for communication, such as a LAN port, USB port, and COM port. It may be referred to as "port," "interface port," "network port," or "computer port."
In the context of "port" or "port number," it may indicate a number used in the transport layer protocol of TCP/IP communications.


LAN stands for Local Area Network.


Transmission Control Protocol (TCP) is a standard protocol used in Internet communications. One-to-one connection-oriented communication known as unicast is used in upper-layer communication protocols, such as HTTP, FTP, and POP.
The TCP specification has been merged into "RFC 9293 TCP" from "RFC 793 TCP" and others.


User Datagram Protocol (UDP) is a standard protocol used in Internet communications. It is also known as multicast or broadcast, which is used to transmit data, such as audio and video, to multiple devices.


Universal Serial Bus (USB) is a standard for serial bus communication, which refers to the communication between a host, such as a computer, and a passively operating peripheral device.
USB Implementers Forum:


Universal Serial Bus Test & Measurement Class (USBTMC) is a USB class (protocol) defined for the GPIB-like control of power supplies and instruments using the Virtual Instrument Software Architecture (VISA).


Universal Serial Bus Communications Device Class (USBCDC) is a USB class (protocol) defined as a virtual COM port that replaces RS-232C with USB.


General-Purpose Interface Bus (GPIB) is a communication standard developed to interface computers with measuring instruments and power supplies. The GPIB cable has piggyback connectors that allow for daisy-chaining multiple instruments and other devices to the GPIB bus. GPIB was the standard communication method for measuring instruments before the prevalence of LAN and USB.


RS-232C is a serial communication standard that connects a computer to external peripherals, such as modems. It was commonly used for computer interfaces before the prevalence of LAN and USB. Communication speeds include 2400 and 9600 bps. Because the communication lines are single-ended rather than differential signals, the communication distance is short and vulnerable to noise. Furthermore, it is limited to one link per port because the number of connections is 1:1.
Communication depends on the alignment of communication speed (bits per second, bps); data bits; parity; stop bits; flow control;  and other device settings.


RS-485, or EIA-485, is a serial bus communication standard that overcomes the limitations of RS-232C and supports a communication speed of 10 Mbps and a long-distance communication of 1.2 km owing to differential signals (balanced transmission method). It also supports N:M connections, which facilitate the connection and usage called multi-drop. The physical layer of CC-Link is a communication protocol compliant with RS-485.


Controller Area Network (CAN) is a serial communication standard developed by Bosch in Germany. It is used for communications involving in-vehicle equipment.

Programming Languages

A programming language is a set of rules for writing programs. It is a mechanism designed to simplify writing instructions to the computer. Languages can be classified into "low-level programming languages," such as machine code and assembly language, and "high-level programming languages," such as C and JAVA.
Programming languages may also refer to programming tools.


LabVIEW is a graphical programming tool (integrated development environment, IDE) for controlling measuring instruments provided by National Instruments. A graphical user interface (GUI) can be used to develop applications for controlling power supplies and instrumentation in low-code or no-code.


MATLAB is MathWorks' numerical analysis software used by scientists and engineers, which can also collect data and control hardware, such as power supplies and instrumentation.

Visual C#

Visual C# is a programming language included in Visual Studio, an IDE provided by Microsoft Corporation.

For Matsusada Precision LXI-supported products, the programming guide included with the IVI driver explains how to control the power supply using Visual C#.

Visual C++

Visual C++ is a programming language included in Visual Studio, an IDE provided by Microsoft Corporation.

For Matsusada Precision LXI-supported products, the programming guide included with the IVI driver explains how to control the power supply using Visual C++.

Visual Basic

Visual Basic is a programming language included in Visual Studio, an IDE provided by Microsoft Corporation.

For Matsusada Precision LXI-supported products, the programming guide included with the IVI driver explains how to control the power supply using Visual Basic.

Visual Basic .net

Visual is a programming language included in Visual Studio, an IDE provided by Microsoft Corporation.


Visual Basic for Applications (VBA) is a programming language for developing applications using Microsoft Excel and Word.


Python is a renowned programming language that simplifies writing code. It is a general-purpose programming language and has applications in the development of AI (Artificial Intelligence).


A protocol is a standard that defines procedures and rules for communication. For example, the following Internet technologies, among others, are standardized in RFCs (Request for Comments) issued by the IETF (Internet Engineering Task Force).
IP: Internet Protocol, RFC 791
TCP: Transmission Control Protocol, RFC 793
UDP: User Datagram Protocol, RFC768
HTTP: Hyper Text Transfer Protocol, RFC7231


A driver or a device driver is a software that acts as an interface between the operating system and the application to operate peripheral or built-in devices.


LAN eXtensions for Instrumentation (LXI) is a communication standard for controlling instruments over a LAN. Matsusada Precision manufactures and sells DC power supplies that conform to LXI standards. Official website:
Matsusada Precision's LXI-compliant products;


Interchangeable Virtual Instrument (IVI) is a driver standard for measuring instruments established by a group of manufacturers and others to improve software compatibility. There are two types of this driver, IVI-C and IVI-COM. Matsusada Precision supplies drivers for both IVI-C and IVI-COM.


Virtual Instrument Software Architecture (VISA) is an implementation of a standard developed by the VXI plug & play Systems Alliance, which defines a standard library for communication using instruments and other devices. I/O control programming can be simplified using VISA, as instructed to the customers by various manufacturers of measuring instruments.


Standard Commands for Programmable Instruments (SCPI) is a command language for controlling instruments and power supplies. SCPI, called Skippy, defines commands, syntax, and data structures that can be commonly used by multiple manufacturers. Various measuring instruments are compliant with the SCPI language, and we also offer a choice of SCPI and original commands for use.
Matsusada Precision supports the PCPI language in the REK/REKJ series of DC power supplies and other products.


Emulation (emulator) is the act of imitating another device. It is the operation in the compatibility mode used to work with other companies' command languages or with older programs.

Command Language

A command language is a language for providing commands to computers and peripherals. Typical examples include DOS and PowerShell commands that you can use at the command prompt, shell scripts with SSH connections to servers, and so on.
For peripheral devices, the manufacturer's own command language is implemented.
Matsusada Precision's equipment implements original and SCPI command languages.
Previously, commands could be sent, received, and controlled using HyperTerminal, which included Windows.


Debugging is the process of finding and removing defects in a program or an electronic device. It also refers to identifying and rectifying defects found during operation testing and verification.


A library is a collection of highly reusable programs (source code). C programs begin with "#include <stdio.h>" in which "stdio.h" is a standard library called header files and "stdio" stands for Standard Input/Output.

Error Traps

An error trap is a countermeasure against an error anticipated in advance, or an error countermeasure program. The process or exception handling program in the event of an error is called error handling.


A subset is a set of parts of the whole. It may also refer to a simplified version of a program with limited functions. For reducing the weight of programs and data, only the necessary functions and data are used as a "subset."


Application Programming Interface (API) is a mechanism for collaboration between application software.

OSI Reference Model

The Open System Interconnection (OSI) reference model is a model that classifies computer communication into seven layers.
Layer 7 - Application Layer
Layer 6 - Presentation Layer
Layer 5 - Session Layer
Layer 4 - Transport Layer
Layer 3 - Network Layer
Layer 2 - Data Link Layer
Layer 1 - Physical Layer


Universal Asynchronous Receiver/Transmitter (UART) is a standard for general-purpose asynchronous transmission and reception.


Serial Peripheral Interface (SPI) is a serial communication standard used for short distances within computers, printed circuit boards (PCBs), and units.
The following signals, among others, are included.
SIMO (Slave In Master Out)
SOMI (Slave Out Master In)
SCLK (Serial Clock)
SS (Slave Select)


Inter-Integrated Circuit (I2C) is a serial communication bus for communication between master and slave devices, which is possible using only two signal lines.


System Management Bus (SMbus) is a protocol for system management using I2C communication. It is used in systems such as industrial equipment to monitor temperature, FAN, and voltage.


Power Management Bus (PMbus) is a protocol for monitoring and controlling power supplies using I2C communication. It is found in digitally controlled embedded power supply modules and batteries.


Programmable Logic Controller (PLC) is a control device for equipment and facilities. The programming language uses graphics based on relay circuits expressed in ladder diagrams.

Ladder/Ladder Language

The ladder language is a programming languages for controlling logic circuits. It is used for describing (programming) the operation of a PLC.

Communication speed

Communication speed describes the amount of time and data sent and received between devices. It is expressed in units such as bps.

Baud rate

Baud rate (baudrate) is a value representing the number of modulation cycles. The unit of baud rate is baud; however, in the COM port of Windows, bps is used as the unit of the baud rate setting item, which has the same meaning.


Bits per second (bps) is a unit of communication speed expressing the amount of data that can be transmitted per second.
G3 standard FAX is 14.4 kbps
Super G3 standard is 33.6 kbps
IEEE802.11 for wireless LAN is 2 Mbps
IEEE802.11a for wireless LAN is 11 Mbps
IEEE802.11b for wireless LAN is 54 Mbps
IEEE802.11g wireless LAN is 54 Mbps
IEEE802.11n for wireless LAN ranges from 65 to 600 Mbps
IEEE802.11ac for wireless LAN ranges from 433 Mbps to 6.93 Gbps
Wired LANs use 100 Mbps or 1 Gbps standards.


Parity is a technique used for error detection in computer communications. The bit assigned to confirm the correctness of the data being sent and received is called the parity bit. Other methods for detecting errors in communication data include checksum and cyclic redundancy check (CRC).


Internet of Things (IoT) describes the collection and control of data from various devices, such as sensors, via the Internet. It is expected that the collection of a large amount of information will be used as big data.


Machine to Machine (M2M) describes information communication between machines. As it is a conceptual term, there are no specific rules. M2M is similar to IoT; however, it does not limit communication to the Internet.

Industry 4.0

The Fourth Industrial Revolution is the trend toward automation and data exchange in manufacturing technologies and processes, including the Internet of Things (IoT), Machine to Machine (M2M), cloud computing, cognitive computing, artificial intelligence (AI), and cyber-physical systems (CPS).

Industrial Ethernet

Industrial Ethernet is an ethernet used for factory networks and systems and devices used in factories. Industrial Ethernet protocols are more synchronous, real-time, and redundant than typical LANs.
Examples of Industrial Ethernet include the following.

For more information, see Tech Tips: Control of industrial networks and power supply devices


Sockets are a form of TCP/IP communication between devices. They are mainly used for communication between clients and servers and programmed using Winsock (Windows Sockets API, WSA).


EtherNet/IP is one of the world's most popular protocols in industrial networking, which applies standard Ethernet to CIP (Common Industrial Protocol).

For more information, see Tech Tips: Control of industrial networks and power supply devices


PROFINET is a technical standard for communication over Industrial Ethernet. It is administered by the PROFIBUS Association.

For more information, see Tech Tips: Control of industrial networks and power supply devices

Official website of the PROFIBUS/PROFINET Association:


PROFIBUS is an industrial communication standard using RS-485.

For more information, see Tech Tips: Control of industrial networks and power supply devices

Official website of the PROFIBUS/PROFINET Association:


CC-Link is an industrial communication standard using RS-485.

Click here for Matsusada Precision's CC-Link compatible products
Compact High Power Supply with power factor correction and worldwide input PK series:

Ultra low ripple programmable dc power supply P4LT Series:

Ultra Slim & Versatile DC Power Supply P4L Series:

Official website of the CC-Link Association:


Modbus is a communication protocol for PLCs developed by Modicon Inc. (now AEG Schneider Automation International S.A.S.). It has gained popularity in industrial electronics communications owing to its publicly available and free-of-charge specifications. Ethernet-based Modbus/TCP is also popular because the physical layer is not defined.

For more information, Tech Tips: Control of industrial networks and power supply devices


Synchronization (SYNC) means matching or matching the timing of signals. In measuring machines and controls, operation in accordance with a reference signal is crucial. Digital and audio/video signals can be correctly communicated by matching with synchronization signals. Clock synchronization uses clock signals for synchronization. In asynchronization, the clock signal line is unused and synchronization is based on start and stop bits.


A variable is a place used in programming to store data of unspecified value. By contrast, a fixed value is called a constant. When using variables in programming, it is necessary to declare the type. (In some programming languages, this is not required.)

Variable types

The type of a variable is the format or range of data going into the variable. When variables are used in programming, their types must be declared in advance.
The kind of type depends on the programming language. Examples of variable types include integer, float, and string.


A bit is the smallest unit of information denoting the first digit of a binary number represented by 0 and 1.


A byte is a unit of information, where 8 bits = 1 byte. Kilobyte (KB), megabyte (MB), gigabyte (GB), and terabyte (TB) are also used as larger units. Originally, the SI prefixes K, M, G, and T denote integer powers of 10; however, in computers, 1 KB is often treated as 10 to the power of 2 = 1024 Bytes, 1 MB = 1024 KB, and 1 GB = 1024 MB.


A word is a unit used in programming to express the amount of information.


A container represents a set of middleware and libraries used to run applications in programming. Generally, a "container" is a "Docker container," a unit that runs in a virtual environment (docker) developed by Docker Inc. Docker is characterized by being lighter than a virtual machine.


A string is a sequence of characters in computers and programming. It is also the type of a variable or constant.


In computers, character refer to letters. The Char type, which stores the character code for a single character in a variable type, is the abbreviation for character.


A packet is a block of data sent and received in communication. In Internet communications, transmitted data are divided into packets by the Internet Protocol (IP). The maximum packet size is determined by the MTU (Maximum Transmission Unit) and is limited to a maximum of 1,500.


An argument is a value passed to a function or subroutine in a program.

Return value

The return value is the value of the result returned from a function or subroutine.


16bit is a method of representing numbers using 16 bits (= 16th power of 2). Furthermore, 16 bits are 2 Bytes, and the maximum number in decimal notation is 65,536.
Digital Measurement and Resolution -Basics of IoT-


32bit is a method of representing numbers using 32 bits (= 32nd power of 2). Furthermore, 32 bits are 4 Bytes, and the maximum number in decimal notation is 4,294,967,296.
Digital Measurement and Resolution -Basics of IoT-


A floating-point is a type of representation of a number that is divided into a mantissa part and an exponent part denoting the location of the decimal point.

Rounding Error (Round-off Error)

A rounding error is a discrepancy in value caused by processing fractions for the convenience of digits in numerical calculations. It is a type of quantization error caused by "rounding off" or "rounding down" or "rounding up" after significant digits.

Precision loss

Precision loss is an error owing to the reduction of significant digits in the results of floating-point calculations. It occurs while subtracting values that are approximately equal or adding values that are almost equal in absolute value but have different signs.


NULL is a state with no data or values.


Overflow is an error that occurs when a value exceeds the range of a variable. Furthermore, writing beyond the specified memory area is called overflow. In the case of buffer area, it is called buffer overflow. In the event of an overflow, pay attention to the type when handling numerical values and error handling in the event of an overflow.


An underflow is an error that occurs when the lower bound of the exponent of a floating-point number is exceeded.


Hexadecimal is a representation method that treats 0-15 as one digit, where 0-9 are numbers and 10-15 are alphabets. The base 16 of a hexadecimal number is called the radix.
See Sheet2 for conversion to and from decimal and binary numbers.


Decimal numbers are a method of expressing numbers using digits from 0 to 9.

See Sheet2 for conversion to and from decimal and binary numbers.


BCD stands for binary-coded decimal. It is a method of expressing a decimal number using four binary digits for each digit.
For example, 1,234 is represented as 0001 0010 0011 0100.


A stack is a data structure in which data that enter later are output first. It is also called LIFO: Last In First Out or FILO: First In Last Out.


A queue is a data structure that outputs data that enter first. It is also known as FIFO: First In First Out and LILO: Last In Last Out.


In programming, wrapper refers to covering up the original function or library. For example, using wrappers for functions that are hardware- or operating-system -dependent increases portability and appropriateness.


Master/slave refers to a system in which a master machine issues commands and a slave machine operates in accordance with those commands.
Because master/slave implies discrimination, its usage is discouraged. Instead, the terms "primary/secondary," "leader/follower," "primary/replica," and "primary/standby" are recommended.

Typical (Typical Value)

Typical refers to "representative (standard)" used in datasheets and other documents to express representative values of specifications. It is abbreviated as Typ.

Nominal (Nominal Value)

Nominal is a name-only value. Nominal Value represents a reference value based on design and a value for identification.


A digit is a number's place value. In power supplies and measuring instruments, it is expressed as 3 1/2 digits when representing the display digits of a front meter. When expressing an error in precision or accuracy, it refers to one count of the least significant digit.