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52-642: The MFi program covers various device connectors including the headphone jack, original dock connector and the newer Lightning connector , as well as AirPlay support. Companies joining the MFi program and passing certification tests are able to display certain MFi-related logos on their product packaging, like the "Made for iPod" badge. The Made for iPod program was launched at the Macworld Expo on 11 January 2005, although some products released just before

104-485: A USB-C port with optional additional functionality. Many mobile devices feature a dock connector. Dock connectors can be used to interface with accessories such as external speakers, including stereo systems and clock radios . Automotive accessories for mobile devices include charging cradles, FM transmitters for playing audio through the car's speakers, and GPS receivers . There are dock connector cables that offer additional capabilities such as direct integration with

156-513: A cross-over , roll-over or null modem cable must be used. Generally, serial port connectors are gendered , only allowing connectors to mate with a connector of the opposite gender. With D-subminiature connectors, the male connectors have protruding pins, and female connectors have corresponding round sockets. Either type of connector can be mounted on equipment or a panel; or terminate a cable. Connectors mounted on DTE are likely to be male, and those mounted on DCE are likely to be female (with

208-433: A phone connector , usually the smaller 2.5 or 3.5 mm connectors and the most basic 3-wire interface—transmit, receive and ground. 8P8C connectors are also used in many devices. The EIA/TIA-561 standard defines a pinout using this connector, while the rollover cable (or Yost standard) is commonly used on Unix computers and network devices, such as equipment from Cisco Systems . Many models of Macintosh favor

260-524: A ribbon cable to the more standard 9-pin DE-9 connector (and frequently mounted on a free slot plate or other part of the housing). The following table lists commonly used RS-232 signals and pin assignments: Signal Ground is a common return for the other connections; it appears on two pins in the Yost standard but is the same signal. The DB-25 connector includes a second Protective Ground on pin 1, which

312-649: A 24-pin electromechanical interface specifications for cellular phone charging, wired data communication, analog audio, etc. The 2007 updated version has only 20 pins but added composite video output support among other changes. The Portable Digital Media Interface (PDMI) is a 30-pin interconnection standard for portable media players . It was developed by the Consumer Electronics Association as ANSI/CEA-2017-A, Common Interconnection for Portable Media Players in February 2010. The standard

364-500: A UART integrated circuit, all these settings can be software-controlled. Hardware from the 1980s and earlier may require setting switches or jumpers on a circuit board. The configuration for serial ports designed to be connected to a PC has become a de facto standard, usually stated as 9600/8-N-1. Serial ports use two-level (binary) signaling, so the data rate in bits per second is equal to the symbol rate in baud . The total speed includes bits for framing (stop bits, parity, etc.) and so

416-473: A bit rate by observing what a connected device is sending and synchronizing to it. The number of data bits in each character can be 5 (for Baudot code ), 6 (rarely used), 7 (for true ASCII ), 8 (for most kinds of data, as this size matches the size of a byte ), or 9 (rarely used). 8 data bits are almost universally used in newer applications. 5 or 7 bits generally only make sense with older equipment such as teleprinters. Most serial communications designs send

468-429: A corrupted transmission with an even number of errors will pass the parity check. A single parity bit does not allow implementation of error correction on each character, and communication protocols working over serial data links will typically have higher-level mechanisms to ensure data validity and request retransmission of data that has been incorrectly received. The parity bit in each character can be set to one of

520-410: A mechanical docking station and port replicator devices that supports and aligns the laptop and sports various single-function ports and a power source that are aggregated into the docking connector. Docking connectors carried interfaces such as keyboard , serial , parallel , and video ports from the laptop and supply power to it. As of 2020 , docking connection options usually can be defined as

572-415: A serial port as a control console for diagnostics, while networking hardware (such as routers and switches ) commonly use serial console ports for configuration, diagnostics, and emergency maintenance access. To interface with these and other devices, USB-to-serial converters can quickly and easily add a serial port to a modern PC. Modern devices use an integrated circuit called a UART to implement

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624-833: A serial port. This IC converts characters to and from asynchronous serial form, implementing the timing and framing of data specified by the serial protocol in hardware. The IBM PC implements its serial ports, when present, with one or more UARTs. Very low-cost systems, such as some early home computers , would instead use the CPU to send the data through an output pin, using the bit banging technique. These early home computers often had proprietary serial ports with pinouts and voltage levels incompatible with RS-232. Before large-scale integration (LSI) made UARTs common, serial ports were commonly used in mainframes and minicomputers , which would have multiple small-scale integrated circuits to implement shift registers, logic gates, counters, and all

676-411: 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. While interfaces such as Ethernet , FireWire , and USB also send data as a serial stream ,

728-619: Is none , with error detection handled by a communication protocol. To allow detection of messages damaged by line noise , electromechanical teleprinters were arranged to print a special character when received data contained a parity error. Stop bits sent at the end of every character allow the receiving signal hardware to detect the end of a character and to resynchronize with the character stream. Electronic devices usually use one stop bit. If slow electromechanical teleprinters are used, one-and-one half or two stop bits may be required. The data/parity/stop (D/P/S) conventional notation specifies

780-462: Is 16 times the fastest bit rate, and the serial port circuit can easily divide this down to lower frequencies as required. The capability to set a bit rate does not imply that a working connection will result. Not all bit rates are possible with all serial ports. Some special-purpose protocols such as MIDI for musical instrument control, use serial data rates other than the teleprinter standards. Some serial port implementations can automatically choose

832-563: Is an electrical connector used to attach a mobile device simultaneously to multiple external resources. Dock connectors typically carry a variety of signals and power, through a single connector, to simplify the process of docking the device. A dock connector may be embedded in a mechanical fixture used to support or align the mobile device or may be at the end of a cable. While dock connectors were originally associated with laptops, many other mobile devices now use them. Classic docking connectors for laptop computers are usually embedded into

884-435: Is an output on a DTE device is an input on a DCE device and vice versa, so a DCE device can be connected to a DTE device with a straight wired cable, in which each pin on one end goes to the same numbered pin on the other end. Conventionally, computers and terminals are DTE, while peripherals such as modems are DCE. If it is necessary to connect two DTE (or DCE) devices together, a cable with reversed TX and RX lines, known as

936-458: Is intended to be connected by each device to its own frame ground or similar. Connecting Protective Ground to Signal Ground is a common practice but not recommended. Note that EIA/TIA 561 combines DSR and RI, and the Yost standard combines DSR and DCD. Operating systems usually create symbolic names for the serial ports of a computer, rather than requiring programs to refer to them by hardware address. Unix-like operating systems usually label

988-419: Is present and powered up so are usually asserted at all times. However, non-standard implementations exist, for example, printers that use DTR as flow control. Software handshaking is done for example with ASCII control characters XON/XOFF to control the flow of data. The XON and XOFF characters are sent by the receiver to the sender to control when the sender will send data, that is, these characters go in

1040-408: Is sent over the same channel as its data. The advantage of hardware handshaking is that it can be extremely fast, it works independently of imposed meaning such as ASCII on the transferred data and it is stateless . Its disadvantage is that it requires more hardware and cabling, and both ends of the connection must support the hardware handshaking protocol used. The advantage of software handshaking

1092-475: Is that it can be done with absent or incompatible hardware handshaking circuits and cabling. The disadvantage, common to all in-band control signaling, is that it introduces complexities in ensuring that control messages get through even when data messages are blocked, and data can never be mistaken for control signals. The former is normally dealt with by the operating system or device driver; the latter normally by ensuring that control codes are escaped (such as in

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1144-569: The Kermit protocol ) or omitted by design (such as in ANSI terminal control ). If no handshaking is employed, an overrun receiver might simply fail to receive data from the transmitter. Approaches for preventing this include reducing the speed of the connection so that the receiver can always keep up, increasing the size of buffers so it can keep up averaged over a longer time, using delays after time-consuming operations (e.g. in termcap ) or employing

1196-793: The 20 signals that are defined by the standard, connectors with fewer pins are often used. While specific examples follow, countless other connectors have been used for RS-232 connections. The 9-pin DE-9 connector has been used by most IBM-compatible PCs since the Serial/Parallel Adapter option for the PC-AT , where the 9-pin connector allowed a serial and parallel port to fit on the same card. This connector has been standardized for RS-232 as TIA-574 . Some miniaturized electronics, particularly graphing calculators and hand-held amateur and two-way radio equipment, have serial ports using

1248-488: The MFi program continues to exist. With the introduction of the iPhone the program name extended to "Made for iPod and Made for iPhone", and then still again with the iPad to become "Made for iPod, iPhone and iPad". The program name officially changed to MFi around 2010, although this term had been used unofficially for some time. The MFi program now also covers the AirTunes system for wirelessly streaming music. AirTunes

1300-410: The announcement carried a "Ready for iPod" label instead. It was reported at that time that Apple would be charging a 10% cut for all products with the logo, and the press described this as a "tax". iPods use an extended headphone jack that allows additional control inputs like mute and volume adjustments, and licenses were available for products plugging into the jack or the dock connector. When using

1352-491: The bits within each byte just before sending and just after receiving. Parity is a method of detecting errors in transmission. When parity is used with a serial port, an extra data bit is sent with each data character, arranged so that the number of 1 bits in each character, including the parity bit, is always odd or always even. If a byte is received with the wrong number of 1s, then it must have been corrupted. Correct parity does not necessarily indicate absence of corruption as

1404-613: The cable connectors being the opposite). However, this is far from universal; for instance, most serial printers have a female DB25 connector, but they are DTEs. In this circumstance, the appropriately gendered connectors on the cable or a gender changer can be used to correct the mismatch. The only connector specified in the original RS-232 standard was the 25-pin D-subminiature, however, many other connectors have been used to save money or save on physical space, among other reasons. In particular, since many devices do not use all of

1456-607: The car's audio system and controls. Apple's proprietary 30-pin connector was common to most Apple mobile devices ( iPhone ( 1st generation ), 3G , 3GS , 4 , 4S ), 1st through 4th generation iPod Touch , iPad , iPad 2 , and iPad (3rd generation) ) from its introduction with the 3rd generation iPod classic in 2003 until the Lightning connector was released in late 2012. Originally, the Apple dock connector carried USB , FireWire , some controls and line-level audio outputs. As

1508-431: The connection must match for data to be received correctly. Bit rates commonly supported include 75, 110, 300, 1200, 2400, 4800, 9600, 19200, 38400, 57600 and 115200 bit/s. Many of these standard modem baud rates are multiples of either 1.2 kbps (e.g., 19200, 38400, 76800) or 0.9 kbps (e.g., 57600, 115200). Crystal oscillators with a frequency of 1.843200 MHz are sold specifically for this purpose. This

1560-415: The control lines of a serial port to monitor external devices, without exchanging serial data. A common commercial application of this principle was for some models of uninterruptible power supply which used the control lines to signal loss of power, low battery, and other status information. At least some Morse code training software used a code key connected to the serial port to simulate actual code use;

1612-471: The data bits within each byte least significant bit first. Also possible, but rarely used, is most significant bit first; this was used, for example, by the IBM 2741 printing terminal. The order of bits is not usually configurable within the serial port interface but is defined by the host system. To communicate with systems that require a different bit ordering than the local default, local software can re-order

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1664-465: The developer's version of iOS 7 at the 2013 WWDC included a new MFi approval for game controllers , either wrap-around designs that clip onto an iOS device, or completely separate wireless models. Developers wishing to integrate their devices and application with HomeKit must also be members of the MFi program in order to get access to specifications, as well as certify their products. Dock connector#30-pin dock connector A dock connector

1716-633: The dock connector, devices are able to control the iPod using a simple serial protocol known as the Apple Accessory Protocol (AAP). This uses a (normally) 19,200 bit/s 8N1 communications signal to send short packets containing commands like "take voice note" or "volume up". With the introduction of the 3rd generation iPods, AAP was available to the headphone connection as well. These signals are used by many Made for iPod devices to allow remote control, including car integration systems. All iPod models have been discontinued by 2022, though

1768-409: The effective data rate is lower than the bit transmission rate. For example, with 8-N-1 character framing, only 80% of the bits are available for data; for every eight bits of data, two more framing bits are sent. A standard series of rates is based on multiples of the rates for electromechanical teleprinters ; some serial ports allow many arbitrary rates to be selected, but the speeds on both sides of

1820-478: The first- to third-generation iPad Air , and the first- and second-generations of the iPad Pro used the Lightning connector, as do some Apple accessories . Apple Lightning connector pins can be accessed from both sides of the connector allowing reversibility. Since the release of the 3rd generation of iPad Pro , the Lightning connector is being phased out in favor of the more universal USB-C . The transition

1872-494: The following: Aside from uncommon applications that use the last bit (usually the 9th) for some form of addressing or special signaling, mark or space parity is uncommon, as it adds no error detection information. Odd parity is more useful than even parity since it ensures that at least one state transition occurs in each character, which makes it more reliable at detecting errors like those that could be caused by serial port speed mismatches. The most common parity setting, however,

1924-435: The framing of a serial connection. The most common usage on microcomputers is 8/N/1 (8N1). This specifies 8 data bits, no parity, 1 stop bit. In this notation, the parity bit is not included in the data bits. 7/E/1 (7E1) means that an even parity bit is added to the 7 data bits for a total of 8 bits between the start and stop bits. Flow control is used in circumstances where a transmitter might be able to send data faster than

1976-400: The iPhone 4, 4S, 4th generation iPod Touch, and the first three iPads. Apple introduced an 8-pin dock connector, named Lightning , on September 12, 2012, as replacement of the 30-pin dock connector. The iPhone 5 to iPhone 14 series, the fifth- to seventh-generation iPod touch , seventh-generation iPod nano , first- to fifth-generation iPad mini , the fourth- to ninth-generation iPad ,

2028-402: The iPod changed, so did the signals in the dock connector. Video was added to the connector. FireWire was phased out of the iPods, which led to a discontinuity in usage of the dock connector. As a result of the popularity of Apple's iPod and iPhone devices using the connector, a cottage industry was created of third-party devices that could connect to the interface. With the discontinuation of

2080-486: The introduction of the Lightning connector , the branding was changed and officially became MFi, a term that had been used unofficially for some time. Lightning also introduced additional protocols that could only be officially supported through the MFi program. In addition to the technical requirements, according to TUAW, Apple also took the opportunity to update the licensing agreement to require all 3rd parties to agree to Apple's supplier responsibility code. The release of

2132-421: The more common devices that are connected to the serial port on a PC. Some of these such as modems and serial mice are falling into disuse while others are readily available. Serial ports are very common on most types of microcontroller , where they can be used to communicate with a PC or other serial devices. Since the control signals for a serial port can be driven by any digital signal , some applications used

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2184-460: The opposite direction to the data being sent. The system starts in the sending allowed state. When the receiver's buffers approach capacity, the receiver sends the XOFF character to tell the sender to stop sending data. Later, after the receiver has emptied its buffers, it sends an XON character to tell the sender to resume transmission. It is an example of in-band signaling , where control information

2236-475: The other logic needed. As PCs evolved serial ports were included in the Super I/O chip and then in the chipset . The individual signals on a serial port are unidirectional and when connecting two devices, the outputs of one device must be connected to the inputs of the other. Devices are divided into two categories: data terminal equipment (DTE) and data circuit-terminating equipment (DCE). A line that

2288-577: The receiver is able to process it. To cope with this, serial lines often incorporate a handshaking method. There are hardware and software handshaking methods. Hardware handshaking is done with extra signals, often the RS-232 RTS/CTS or DTR/DSR signal circuits. RTS and CTS are used to control data flow, signaling, for instance, when a buffer is almost full. Per the RS-232 standard and its successors, DTR and DSR are used to signal that equipment

2340-416: The related RS-422 standard, mostly using circular mini-DIN connectors . The Macintosh included a standard set of two ports for connection to a printer and a modem, but some PowerBook laptops had only one combined port to save space. 10P10C connectors can be found on some devices. Another common connector is a 10 × 2 pin header common on motherboards and add-in cards which is usually converted via

2392-637: The serial port devices /dev/tty* . TTY is a common trademark-free abbreviation for teletype , a device commonly attached to early computers' serial ports, and * represents a string identifying the specific port; the syntax of that string depends on the operating system and the device. On Linux , 8250 / 16550 UART hardware serial ports are named /dev/ttyS* , USB adapters appear as /dev/ttyUSB* and various types of virtual serial ports do not necessarily have names starting with tty . The DOS and Windows environments refer to serial ports as COM ports: COM1, COM2,..etc. This list includes some of

2444-572: The sixth-generation 160 GB iPod Classic and the iPhone 4S , the last Apple products to feature the original 30-pin connector, the connector was discontinued in September 2014 but the production of 30-pin connectors in India and developing markets still continued until February 2016. However, Apple does continue to sell and produce a 30-pin-to-USB cable, as well as a 30-pin VGA adapter compatible with

2496-551: The status bits of the serial port could be sampled very rapidly and at predictable times, making it possible for the software to decipher Morse code. Serial computer mice may draw their operating power from the received data or control signals. Serial standards provide for many different operating speeds as well as adjustments to the protocol to account for different operating conditions. The most well-known options are speed, number of data bits per character, parity, and number of stop bits per character. In modern serial ports using

2548-513: The term serial port usually denotes hardware compliant with RS-232 or a related standard, such as RS-485 or RS-422 . Modern consumer personal computers (PCs) have largely replaced serial ports with higher-speed standards, primarily USB. However, serial ports are still frequently used in applications demanding simple, low-speed interfaces, such as industrial automation systems, scientific instruments, point of sale systems and some industrial and consumer products. Server computers may use

2600-452: Was complete for all new models of iPads since March 18, 2022 and iPhones since September 22, 2023. The Samsung Galaxy Tab and Galaxy Note 30-pin dock/charging connector is very similar to – although not identical with – the non-proprietary PDMI connector . It is unrelated to the Apple 30-pin connector. The 2001 Korean Telecommunications Technology Association (TTA) "Standard on I/O Connection Interface of Digital Cellular Phone" defined

2652-440: Was developed with the input or support of over fifty consumer electronics companies worldwide. The WM-PORT is a 22-pin dock connector from Sony , used for the majority of Walkman digital media players since 2006. It provides a data and power connection including to peripherals. Serial port A serial port is a serial communication interface through which information transfers in or out sequentially one bit at

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2704-560: Was originally introduced in 2004 on the Mac and PC platforms inside iTunes , and later became known as AirPlay when video-out capabilities were added to support devices like the Apple TV . AirPlay came to the devices when they gained WiFi capabilities with the introduction of the iPhone and iPod Touch . With no hardware component, AirPlay has been widely implemented in both official and non-MFi software systems (see AirPlay for details). With

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