This article needs additional citations for verification .(October 2020) |
Type | RS-423 serial | ||
---|---|---|---|
Production history | |||
Designer | Digital Equipment Corporation | ||
Pinout | |||
Pin 1 | Data terminal ready | DTR | |
Pin 2 | Transmit data | Tx+ | |
Pin 3 | Transmit data ground | Tx- | |
Pin 4 | Receive data ground | Rx- | |
Pin 5 | Receive data | Rx+ | |
Pin 6 | Data set ready | DSR |
The Modified Modular Jack (MMJ) is a small form-factor serial port connector developed by Digital Equipment Corporation (DEC). It uses a modified version of the 6P6C modular connector with the latch displaced off-center so standard modular connectors found on Ethernet cables or phone jacks cannot accidentally be plugged in. MMJ connections are used on Digital minicomputers, such as the PDP-11, VAX and Alpha systems, and to connect terminals, printers, and serial console servers. [1]
The MMJ connector has six conductors. As defined by DEC, the six pins are Tx and Rx for the data transmission, their return paths, and DSR and DTR for handshaking. The transmit and receive signals are differential: each signal is the voltage difference between the line and its associated ground, as opposed to a voltage on a single connector relative to a common reference. The electrical signaling is defined by the EIA RS-422 standard. The system can interoperate with RS-232 signaling by shorting the lower voltage sides of each signal to the RS-232 signal ground line. In this case, RS-232 limits apply to data rate and cable length.
When connecting two DTE devices such as a computer and a printer, the Digital BC16E crossover cable is used.
The DEC VT320 and TI/HP-928 were terminals offering an MMJ option. Using RS-422 signaling over 6-conductor RJ12, cables could be up to 1000 meters. [2] [ failed verification ]
Thrustmaster is using the MMJ connector for connecting its line of rudder pedals and racing pedals to either USB via a proprietary Thrustmaster Adapter, or directly to a joystick or racing wheel.[ citation needed ]
The Lego Mindstorms NXT and EV3 set used connectors similar to MMJ for motors and sensors. This was to prevent the connection of standard telephone cords. The MMJ connector used by LEGO is also taller than those used with data terminals. [3]
CEA-909 uses the MMJ connector for control signals to a smart antenna, which can either physically or electrically rotate for maximum signal strength.
In telecommunications, RS-232 or Recommended Standard 232 is a standard originally introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a DTE such as a computer terminal or PC, and a DCE, such as a modem. The standard defines the electrical characteristics and timing of signals, the meaning of signals, and the physical size and pinout of connectors. The current version of the standard is TIA-232-F Interface Between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing Serial Binary Data Interchange, issued in 1997. The RS-232 standard had been commonly used in computer serial ports and is still widely used in industrial communication devices.
A terminal adapter or TA is a device that connects a terminal device – a computer, a mobile communications device, or other – to a communications network.
On electronics especially computers, a serial port is a serial communication interface through which information transfers in or out sequentially one bit at a time. This is in contrast to a parallel port, which communicates multiple bits simultaneously in parallel. Throughout most of the history of personal computers, data has been transferred through serial ports to devices such as modems, terminals, various peripherals, and directly between computers.
GeoPort is a serial data system used on some models of the Apple Macintosh that could be externally clocked to run at a 2 megabit per second data rate. GeoPort slightly modified the existing Mac serial port pins to allow the computer's internal DSP hardware or software to send data that, when passed to a digital-to-analog converter, emulated various devices such as modems and fax machines. GeoPort could be found on late-model 68K-based machines as well as many pre-USB Power Macintosh models and PiPPiN. Some later Macintosh models also included an internal GeoPort via an internal connector on the Communications Slot. Apple GeoPort technology is now obsolete, and modem support is typically offered through USB.
Electronic test equipment is used to create signals and capture responses from electronic devices under test (DUTs). In this way, the proper operation of the DUT can be proven or faults in the device can be traced. Use of electronic test equipment is essential to any serious work on electronics systems.
RS-422, also known as TIA/EIA-422, is a technical standard originated by the Electronic Industries Alliance, first issued in 1975, that specifies electrical characteristics of a digital signaling circuit. It was meant to be the foundation of a suite of standards that would replace the older RS-232C standard with standards that offered much higher speed, better immunity from noise, and longer cable lengths. RS-422 systems can transmit data at rates as high as 10 Mbit/s, or may be sent on cables as long as 1,200 meters (3,900 ft) at lower rates. It is closely related to RS-423, which uses the same signaling systems but on a different wiring arrangement.
One meaning of system console, computer console, root console, operator's console, or simply console is the text entry and display device for system administration messages, particularly those from the BIOS or boot loader, the kernel, from the init system and from the system logger. It is a physical device consisting of a keyboard and a printer or screen, and traditionally is a text terminal, but may also be a graphical terminal. System consoles are generalized to computer terminals, which are abstracted respectively by virtual consoles and terminal emulators. Today communication with system consoles is generally done abstractly, via the standard streams, but there may be system-specific interfaces, for example those used by the system kernel.
The D-subminiature or D-sub is a common type of electrical connector. They are named for their characteristic D-shaped metal shield. When they were introduced, D-subs were among the smallest connectors used on computer systems.
Null modem is a communication method to directly connect two DTEs using an RS-232 serial cable. The name stems from the historical use of RS-232 cables to connect two teleprinter devices or two modems in order to communicate with one another; null modem communication refers to using a crossed-over RS-232 cable to connect the teleprinters directly to one another without the modems. It is also used to serially connect a computer to a printer, since both are DTE, and is known as a Printer Cable.
RS-485, also known as TIA-485(-A) or EIA-485, is a standard, originally introduced in 1983, defining the electrical characteristics of drivers and receivers for use in serial communications systems. Electrical signaling is balanced, and multipoint systems are supported. The standard is jointly published by the Telecommunications Industry Association and Electronic Industries Alliance (TIA/EIA). Digital communications networks implementing the standard can be used effectively over long distances and in electrically noisy environments. Multiple receivers may be connected to such a network in a linear, multidrop bus. These characteristics make RS-485 useful in industrial control systems and similar applications.
The RS-449 specification, also known as EIA-449 or TIA-449, defines the functional and mechanical characteristics of the interface between data terminal equipment, typically a computer, and data communications equipment, typically a modem or terminal server. The full title of the standard is EIA-449 General Purpose 37-Position and 9-Position Interface for Data Terminal Equipment and Data Circuit-Terminating Equipment Employing Serial Binary Data Interchange.
In computer networking, DECserver initially referred to a highly successful family of asynchronous console server / terminal server / print server products introduced by Digital Equipment Corporation (DEC) and later referred to a class of UNIX-variant application and file server products based upon the MIPS processor. In February 1998, DEC sold its Network Products Business to Cabletron, which then spun out as its own company, Digital Networks, in September 2000.
Lego Mindstorms NXT is a programmable robotics kit released by Lego on August 2, 2006. It replaced the Robotics Invention System, the first-generation Lego Mindstorms kit. The base kit ships in two versions: the retail version and the education base set. It comes with the NXT-G programming software or the optional LabVIEW for Lego Mindstorms. A variety of unofficial languages exist, such as NXC, NBC, leJOS NXJ, and RobotC. A second-generation set, Lego Mindstorms NXT 2.0, was released on August 1, 2009, with a color sensor and other upgrades. The third-generation EV3 was released in September 2013.
A modular connector is a type of electrical connector for cords and cables of electronic devices and appliances, such as in computer networking, telecommunication equipment, and audio headsets.
RS-423, also known as TIA/EIA-423, is a technical standard originated by the Electronic Industries Alliance that specifies electrical characteristics of a digital signaling circuit. Although it was originally intended as a successor to RS-232C offering greater cable lengths, it is not widely used.
HP X-Terminals are a line of X terminals from Hewlett Packard introduced in the early- to mid-1990s, including the 700/X and 700/RX, Envizex and Entria, and the Envizex II and Entria II. They were often sold alongside PA-RISC-based HP 9000 Unix systems. The primary use case was connecting several graphical consoles to a single server or workstation to allow multiple users access the same (expensive) processing system from terminal systems. These X-Terminals all allowed high-resolution, color-graphics access to the main server from which they downloaded their operating system and necessary program files. All models featured limited expandability, in most cases additional I/O options for peripherals and memory for more programs or local storage. HP did not use its own PA-RISC platform for these systems, the first design used an Intel CISC processor, while all later systems used RISC platforms, first Intel i960 and later the popular MIPS.
Data Terminal Ready (DTR) is a control signal in RS-232 serial communications, transmitted from data terminal equipment (DTE), such as a computer, to data communications equipment (DCE), for example a modem, to indicate that the terminal is ready for communications and the modem may initiate a communications channel.
A USB-to-serial adapter or simply USB adapter is a type of protocol converter that is used for converting USB data signals to and from serial communications standards. Most commonly the USB data signals are converted to either RS-232, RS-485, RS-422, or TTL-level UART serial data. The older serial RS-423 protocol is rarely used any more, so USB to RS423 adapters are less common.
LEGO Mindstorms EV3 is the third generation robotics kit in LEGO's Mindstorms line. It is the successor to the second generation LEGO Mindstorms NXT kit. The "EV" designation refers to the "evolution" of the Mindstorms product line. "3" refers to the fact that it is the third generation of computer modules - first was the RCX and the second is the NXT. It was officially announced on January 4, 2013, and was released in stores on September 1, 2013. The education edition was released on August 1, 2013. There are many competitions using this set, including the FIRST LEGO League Challenge and the World Robot Olympiad, sponsored by LEGO.