A single Thunderbolt port supports up to six Thunderbolt devices via hubs or daisy chains as many of these as the host has DP sources may be Thunderbolt monitors.

Thunderbolt controllers multiplex one or more individual data lanes from connected PCIe and DisplayPort devices for transmission via two duplex Thunderbolt lanes, then de-multiplex them for use by PCIe and DisplayPort devices on the other end. Thunderbolt 2 port on MacBook Pro with Retina display. Thunderbolt 1 and 2 use the same connector as Mini DisplayPort (MDP), whereas Thunderbolt 3 and 4 reuse the USB-C connector from USB. Up to six peripherals may be supported by one connector through various topologies. Thunderbolt combines PCI Express (PCIe) and DisplayPort (DP) into two serial signals, and additionally provides DC power, all in one cable. It was initially marketed under the name Light Peak, and first sold as part of an end-user product on 24 February 2011. It has been developed by Intel, in collaboration with Apple. Thunderbolt is the brand name of a hardware interface for the connection of external peripherals to a computer. HS1TX(P) of the source is connected to HS1RX(P) of the sink.

The cable is actually a crossover cable, it swaps all receive and transmit lanes e.g. This is the pinout for both sides of the connector, source side and sink side.

Thunderbolt 4: 4× PCI Express 3.0, DisplayPort 2.0, USB4.

Thunderbolt 3: 4× PCI Express 3.0, DisplayPort 1.2, USB 3.1 Gen 2.

Thunderbolt 2: 4× PCI Express 2.0, DisplayPort 1.2.

Thunderbolt 1: 4× PCI Express 2.0 DisplayPort 1.1a.

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