Overview of Digital and Analog Connections VGA VGA or Video Graphics Array refers to display hardware that was introduced with the IBM PS/ line of computers in 197. Due to the widespread adoption of the technology, VGA has become the colloquial term used to describe the analog computer video signal that is produced or received by a computer or monitor as well as the HD1 connector. This signal and connector have long been the standardd for computer video. The HD1 connector is a DB-style connector that contains three rowss of five pins for a total of fifteen pins. Many of the cables sold today that use the HD1 connector omit the 9 th pin leaving a total of pins. The original purpose of this pin was to carry +VDC power from the video card in order to power accessories. Since these accessories were never widely adopted, this pin is no longer used and is omitted from cables designed for computer video. The analog computer video signal is composed of five different components, red video, green video, blue video, horizontal sync, and vertical sync (RGBHV). The red, green and bluee signals represent the image s color information, while the sync lines provide the blue print to construct the image. In addition to the video signal, a VGA cable will also carry identificationn information from the monitor to the computer. Digital Display Channel (DDC) and the companion signal Extended Display Identification Dataa (EDID) make computer monitors Plug and Play devices. The DDC and EDIDD information provide the computer s video card with the monitor ss capabilities and supported graphic modes. Pin 1 Function Red Video Green Video Description Carries the Red color information of the video signal Carries the Green color information of the video signal 3 4 6 Blue Video Reserved H.Sync Red Carries Blue color information of the video signal Before E-DDC this carried identification information from the monitor, this pin is now Reserved/Unused Electrical ground for the Horizontal Sync signal Electrical ground for the red color information of the video signal 7 9 10 1 13 Green Electrical ground for the green color information of the video signal Blue Electrical ground for the blue color information of the videoo signal Reserved/ /+ Reserved/Unused. In the original specification this carried power from the video card to a monitor VDC for the purpose of supporting future features. V.Sync/DDC Electrical ground for the Vertical Sync and DDC signals Before E-DDC this carried identification information from the monitor, this pin is now Reserved Reserved/Unused DDC Data Carries identification information, EDID, from the monitor. (SDA) H.Sync Carries Horizontal Sync signal used to build the video image 1 V.Sync DDC Clock (SCL) Carries Vertical Sync signal used to build the video image Carries identification information, EDID, from the monitor.
High Definition Multimedia Interface ( ) is a term that is usedd to describee a set of connectors, as well as an uncompressed digital audio/video signal. was created by major electronics manufacturers, including, Hitachi, Philips, Sony, Toshiba, and others. was the first uncompressed all digital interface that was able to carry both audio and video signals. Though commonly found on consumer electronic devices such as Blu-ray player, the interface is now used as an audio/video output forr laptops and desktops computers. Per the latest specification, version 1.4, there are four different connectors types defined. The type A connector is the most common. The type A connector is a 19-pin connector and is used on devices such as laptop and desktop computers, Blu-ray players, etc.. The type B connector has 9 pins and is capable of carrying double the bandwidth of the type A connector. This connector is designed for future high-resolution (WQUXGA - 340 x 400) displays and has not yet been used on current devices. The type C, or Mini connector is smaller than the type A connector, but uses the same 19-pin configuration. This connector is commonly found on portable devices such as handheld video cameras. The type D, or Micro connector is smaller than the type C connector, but also uses the same 19-pin configuration. This connector is commonly found on small portable devices such as a Smartphone. The final connector is the type E, or Automotive connector which uses the same 19-pin configuration. This connector is designed to be used for in-vehicle HD content distribution and to meet the rigors and environmental issues commonly found in automobiles, such as heat, vibration and signal interference. specifications outline the features that are included with the audio/video signal, i.e. Ethernet channel, audio return channel, 3D, etc. The specification has also outlined five different cable types: Standard Speed, Standard Speed with Ethernet, Standard Automotive, High Speed, and High Speed with Ethernet. Standard Speed cables are capable of reliably supporting 100i or 70p video resolutions. Standard Speed with Ethernet cables support the same resolutions as Standard Speed cables as well as supporting the Ethernet channel functionality. Standard Automotive Cables support the same resolutions as Standard Speed, are designed to be used for in-vehicle HD content distribution, and to meet the rigors and environmental issues commonly found in automobiles. High Speed cables are designed and tested to support resolutions of 100p and beyond as well as advanced features. High Speed with Ethernet cables support the same resolutions and features as the High Speed cables as well as the Ethernet channel functionality. In addition to the audio/video signal and features, the signal includes content protection. High-Bandwidth Digital Content Protection (HDCP) was created by Intel to protect digital content such as movies and programming from unauthorized duplication. HDCP require that devices exchange information in the form of a digital handshake before content will be displayed. All of these signals, audio and video, features, and content protection, are carried by Transition Minimized Differential Signalingg (TMDS). The number of TMDS links is used to categorize the connector types. Type A, C, D, and E connectors have one TMDS link and are considered single-link connectors. Type B connectors have two TMDS links and are considered dual-link connectors. The second TMDS link in the type B connector allows more information to be carried over the cable which allows for higher resolutions.
Pin 1 Function Description TMDS Data + Carries audio andd video data TMDS Data Shield Electrical groundd for the audio and video TMDS lines 3 4 TMDS Data - Carries audio andd video data TMDS Data 1 + Carries audio andd video data TMDS Data Shield Electrical groundd for the audio and video TMDS lines 6 7 TMDS Data 1 - Carries audio andd video data TMDS Data 0 + Carries audio andd video data TMDS Data 0 Shield Electrical groundd for the audio and video TMDS lines 9 10 TMDS Data 0 - Carries audio andd video data TMDS Clock + Carries information that aids in signal synchronization TMDS Clock Shield Electrical groundd for the TMDS Clock lines 1 TMDS Clock - Carries information that aids in signal synchronization 13 1 16 17 CEC Reserved DDC Clock (SCL) DDC Data (SDA) DDC/CEC Carries control and command data between devices, Consumer Electronics Control (CEC). Unused. Reserved for future use Carries identification information,, EDID, between the source and display device Carries identification information,, EDID, between the source and display device Electrical groundd for the DDC andd CEC signals 1 19 +V Power Hot Plug Detect Carries a +VDCC power supply from the source device Monitors power up/down and connect/disconnectt events DisplayPort DisplayPort is a digital display standard proposed by the Video Electronics Standards Association (VESA). The standard defines a royalty-freee digital audio/video interconnect that is intended to connect a computer to a computer monitor or HDTV. This connector was designed to replace the VGA and DVI connectors that are commonly used for the video output of a computer. Though DisplayPort offers the same functionality as the connector, it is not expected to replace the connector in consumer electronics. Theree are two different types of the DisplayPort connector, internal and external. The internal connector has 30/0 pins and is designed to provide a connection between a graphics card and a built in flat
panel. This type of connector would be found inside of laptop computers. The external connector has 0 pins and is secured by latch clips. This type of connector is found on computers, computer monitors, HDTVs, etc. DisplayPort signals are composed of a unidirectional main link which carries the audio/video data and a half-duple bidirectional auxiliary channel which carries monitor information. The DisplayPort signal is carried by micro data packets. This means that the signal is not directly compatible with or DVI. However, dual-mode DisplayPort video cards are able to transmit single-link and DVI signals through a passive video adapter. Active powered video adapters allow for signal conversion to Dual-Link DVI and analog VGA. Pin Pin Description 1 Main Link Lane 0 + Carries audio and video data Main Link Lane 0 3 Main Link Lane 0 - Carries audio and video data 4 Main Link Lane 1 + Carries audio and video data Main Link Lane 1 6 Main Link Lane 1 - Carries audio and video data 7 Main Link Lane + Carries audio and video data Main Link Lane 9 Main Link Lane - Carries audio and video data 10 Main Link Lane 3 + Carries audio and video data Main Link Lane 3 1 Main Link Lane 3 - Carries audio and video data 13 Electrical ground Electrical ground 1 Aux Ch + Bidirectional data carried between the monitor and the source 16 Aux Ch Electrical ground for the Aux channel 17 Aux Ch - 1 Hot Plug Detect Bidirectional data carried between the monitor and the source Monitors power up/down and connect/disconnect events 19 Power Return Power return from the monitor 0 Power (3.3V 00mA) Power provided to the monitor
DVI Digital Visual Interface (DVI) is a video interface that was designed by an industry consortium, the Digital Display Working Group (DDWG), to replace VGA. There are two different types of DVI connector, DVI-I and DVI-D. DVI-II carries an uncompressed digital video signal and is also capable of carrying an analog video signal. DVI uses TMDS to transmit the video data and both Single-Link and Dual-Link connections are possible. The two different types of DVI connectors are distinguished by the pinn configuration. Both connector types will have a grounding bar, pin #C, which is separate from the pins. The DVI-I connector has four additional pins that surround the grounding bar. The DVI-D connector does not have any pins surrounding the grounding bar. The number of pins in a DVI connector will also indicate whether the cable will support a Single-Link or a Dual-Link TMDS connection. A Single-Link DVI connector, DVI-I or r DVI-D, will have three rows of six pins for a total of eighteen pins. Six pins in the middle of the connector will not be present. A Dual-Link DVI connector, DVI-I or DVI-D will have three rows of eight pins for a total of twenty-four pins. The full complement of twenty-four pins allows the Dual-Link DVI connectors to carry an additional TMDS link which allows for the support of higher resolution video. The digital DVI signal is identical to the signal minus the audio portion. The digital signal is supported by both the DVI-II and DVI-D connector. Adapter cables that have both a DVI-D connector and connector can be used to connect an monitor to a DVI-I or DVI-D video output on a computer. DVI-I connectors also have the ability to carry analog video signals. The analog DVI signal is identical to the VGA signal. Adapter cables that have both a DVI-I and VGA connector can be used to connect a VGA monitor to a DVI-I video output t on a computer. Pin 1 3 4 Function Description TMDS Data - Carries Video Data TMDS Data + Carries Video Data TMDS Data /4 Shield Electrical ground forr the video TMDS lines TMDS Data 4 - Carries Video Data (Dual-Link only) TMDS Data 4 + Carries Video Data (Dual-Link only) 6 DDC Clock (SCL) Carries identificationn information, EDID, from the monitor. 7 9 10 DDC Data (SDA) Carries identificationn information, EDID, from the monitor. Carries Vertical Sync information used to build an analog V.Sync (DVI-I only) video image TMDS Data 1 - Carries Video Data TMDS Data 1 + Carries Video Data TMDS Data 1/3 Shield Electrical ground forr the video TMDS lines 1 13 TMDS Data 3 - Carries Video Data (Dual-Link only) TMDS Data 3 + Carries Video Data (Dual-Link only) 1 16 +V Power Hot Plug Detect Carries a +VDC power supply from the source device Electrical ground Monitors power up/down and connect/disconnect events 17 TMDS Data 0 - Carries Video Data
1 TMDS Data 0 + Carries Video Data 19 TMDS Data 0/ Shield Electrical ground for the Video TMDS lines 0 TMDS Data - Carries Video Data (Dual-Link only) 1 TMDS Data + Carries Video Data (Dual-Link only) TMDS Clock Shield Electrical ground for the TMDS Clock lines 3 TMDS Clock + Carries information that aids in signal synchronization 4 TMDS Clock - Carries information that aids in signal synchronization C1 C C3 C4 C Red Video (DVI-I only) Green Video (DVI-I only) Blue Video (DVI-I only) H.Sync (DVI-I only) Common (DVI-I only) Carries the Red video information of an analog video signal. DVI-I only Carries the Green video information of an analog video signal. DVI-I only Carries Blue video information of an analog video signal. DVI-I only Carries Horizontal Sync signal used to build an analog video image Electrical ground for Red, Green, and Blue video data. Unused in a DVI-D cable Summary VGA Type A Type B Type C, D, E DisplayPort Internal DisplayPort External DVI-I DVI-D Signal Analo Digital or Digital Digital Digital Digital Digital Digital Type g Analog 4+4+1 4+1 Pin Count 19 9 19 0/30 0 (1) 1+4+1 1+1 Audio No Yes Yes Yes Yes Yes No No Distance 7ft 1 (49.ft) 1 (49.ft) CG is a division of Lastar Inc. CG, TruLink and RapidRun are trademarks or registered trademarks of Lastar Inc. in the U.S. and / or in other countries. All other third party trademarks are the property of their perspective owners. This white paper is for informational purposes only and is subject to change without notice. CG makes no guarantees, either expressed or implied, concerning the accuracy, completeness or reliability of the information found in this document.