Once you have selected a docking station, an important element to consider is how to connect your displays to the unit and what video cables or adapters may be required. There are several different types of video connectors available and it can get confusing, so let’s break them down individually and simply:
VGA (Ok)—The oldest style video connection available, carries an analog video signal up to 1920×1200 resolution. A standard VGA cable has a VGA connector on both ends of the cable (also referred to as a VGA to VGA cable). In general cannot be converted to other video types unless a proprietary adapter is used.
DVI (Good)—First digital video connection used for PCs, carries a digital video signal up to 1920×1200 resolution. A standard DVI cable has a DVI connector on both ends of the cable (also referred to as a DVI to DVI cable). A DVI-I output can be converted to VGA using an adapter. All Plugable products that have a DVI output are of the DVI-I variety, and include a DVI to VGA adapter in the box.
DVI can also be converted to HDMI by using a separate adapter, or there are cables that have a DVI connector on one end and an HDMI connector on the other. A DVI to HDMI cable is bi-directional.
HDMI (Better)—Most common type of video connection for modern televisions, also featured on many modern monitors. Carries a digital video signal up to 3840×2160 (as well as audio) depending on the version of HDMI specification in use by both the source (output) and receiving device (input). Can be converted to DVI by using a separate adapter, or there are cables that have a HDMI connector on one end and an DVI connector on the other. A HDMI to DVI cable is bi-directional.
DisplayPort (Best)—A common type of video connection used in modern monitors, similar in many ways to HDMI but uses a fundamentally different protocol (typically not found in televisions). Carries a digital video signal up to 4096×2160 (as well as audio) depending on the version of DisplayPort (DP) specification in use by both the source (output) and receiving device (input).
Can be converted to HDMI, DVI or VGA using adapters, of which there are two possible types, Active and Passive. An active adapter is as the name implies, it ‘actively’ converts the video signal to a different type. A passive adapter only provides for the conversion of the physical connector type, and does not change the video signal itself.
The type of adapter required depends on the capabilities of the source DisplayPort output. A ‘Dual Mode’ DisplayPort (also known as DP++) can use passive adapters while a ‘pure’ DisplayPort port requires Active adapters. Plugable offers products with both types.
In general, the best approach is to first determine what types of video inputs are available on the displays you wish to attach to the dock. Once that information is in hand, you can compare that to the available video outputs offered by our various docks. With both ‘ends’ of the connection known, you can determine what types of video cables and adapters will be needed to connect your displays.