USB Type-CTM calls for a cable with 24 signals
|Pin Number||Signal Name||Description|
|A1, B1, A12, B12||GND||Ground|
|A4, B4, A9, B9||VBUS||Power UFP|
|A5||CC||Used in Power Delivery Protocol signalling|
|B5||VCONN||Supplies Power to Electronically Marked Cables|
|A6||D+||USB 2.0 legacy signal, also used by USB 3.x|
|A7||D-||USB 2.0 legacy signal, also used by USB 3.x|
|A2, A3||SSTX1+ / SSTX1-||Differential Transmit Signal 1 for USB 3.x|
|B11, B10||SSRX1+ / SSRX1-||Differential Transmit Signal 1 for USB 3.x|
|B2, B3||SSTX2+ / SSTX2-||Differential Transmit Signal 1 for USB 3.x|
|A11, A10||SSRX2+ / SSRX2-||Differential Transmit Signal 1 for USB 3.x|
|A8||SBU1||Used in Alternate Mode only|
|A8||SBU2||Used in Alternate Mode only|
There are three types of USB Type-C cables. Depending on the type of cable used, not all signals are required.
Passive Type-CTM cable
Passive cables are required to carry the USB 2.0 compliant signals: CC and VCONN. SuperSpeed and SuperSpeed Plus protocols cannot be run on passive cables. Passive cables do not work with the Power Delivery Protocol, but can allow the DFP to advertise and deliver additional power for current mode operation (see the Power Delivery Page for more details on power delivery options of USB )
Electronically Marked Powered Cable (EMCA)
Electronically Marked Powered Cables carry all Type-C signals and are capable of running all USB 3.1 speeds. Inside of these cables is an integrated circuit used to process the Power Delivery communication protocols. The electronic marking allows for role switching, alternate mode selection, and enhanced power options. (Details of how these three items are implemented is provided on the Power Deliver Protocol page.)
The embedded electronics are powered by VCONN. Type-C requires that both CC1 and CC2 be capable of performing both the VCONN and CC functions.
Managed Active Power Cables
Managed Active Power Cables have the same basic circuitry as electronically marked cables, but have additional signal reconditioning capability. Managed Active Power Cables are needed to extend the cable length.