Confusing Mini DisplayPort with Thunderbolt

Apple's new Thunderbolt technology uses the same DisplayPort connection that has been available in older Macs, which may be a source of confusion down the line for some users.

Topher Kessler MacFixIt Editor
Topher, an avid Mac user for the past 15 years, has been a contributing author to MacFixIt since the spring of 2008. One of his passions is troubleshooting Mac problems and making the best use of Macs and Apple hardware at home and in the workplace.
Topher Kessler
2 min read

In the last few years Apple has been releasing systems with an advanced Mini DisplayPort connection for monitors that allows for some advanced options such as using an iMac as an external display. This port has been adopted throughout Apple's line of Mac systems because it offers high-resolution video handling as well as other options like audio support for connecting to television systems.

In a recent knowledgebase article on the DisplayPort connection, Apple describes how to identify whether or not your system has a DisplayPort connection, noting the port's geometry as well as the symbols used to identify it, along with various Apple-supplied adapters that work with DisplayPort.

Thunderbolt and DisplayPort connections
Apple's new Thunderbolt (left) and older DisplayPort connections use the same port geometry. Apple

As with most other ports Apple has used (USB, FireWire 400, FireWire 800, DVI, etc.), DisplayPort has had a unique connector; but with the release of Apple's new "Thunderbolt" technology in the latest MacBook systems, Apple threw in a potential source of confusion by using the same DisplayPort connector.

The new port is backward compatible so it can still be used to connect to DisplayPort devices; however, only the new port can be used to connect to Thunderbolt devices.

This means that while you can physically connect a Thunderbolt device to a Mac with DisplayPort, the device will not work, but if you connect a DisplayPort device to a Mac with Thunderbolt, then the device will work.

DisplayPort devices will work with Thunderbolt, but Thunderbolt devices will not work with DisplayPort

The main warning here is to be aware of and avoid situations when setting up or troubleshooting devices where you might confuse the two connections when you need to use the Thunderbolt technology. These can include connections to new high-throughput storage devices (and future unreleased devices), or when troubleshooting new Mac systems by connecting them in Target Disk mode, which is supported on the Thunderbolt connection.

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