♦What does it mean when a high-frequency line exceeds several Gs?
■ Performance indicators of wire transmission
Low frequency: below 12KHz, the main parameter is capacitance, characteristic capacitance imbalance
High frequency: above 12KHz, the parameters include attenuation, crosstalk, delay, delay difference, characteristic impedance, transmission speed, etc.
Common high frequency related units and conversions dB decibel, mainly used to describe sound units, attenuation and crosstalk, etc. Hz Hertz, the unit of frequency Ω Ohm, the unit of impedance Ps, ns, picosecond, nanosecond, the unit of time Unit conversion: (thousands) T Tera (1012) G Giga (109) M Mega (106) K Kilo (103) ★ International Unit m Milli (10-3) μ Micro (10-6) n Nano (10-9) p Picos (10-12) f Feminine (10-15)
■ The number of meters and Gs of high-frequency cables refers to comparing the test data of the actual test cable with the test specifications. If the parameters meet the test specifications, it means it has passed. If the parameters do not meet the test specifications, it means it has failed!
♦What is the difference between USB Power Delivery (USB PD) and USB Type-C?
■ USB Power Delivery (USB PD) is a protocol specification that supports both power delivery of up to 100W and data communication over a single cable.
■ USB Type-C is a new, reversible USB connector specification that supports a variety of new standards, including USB 3.1 (Gen 1 and Gen 2), Display Port, HDMI, and USB PD.
■ USB Type-C ports support power delivery of up to 5V/3A by default. If USB PD is implemented in a USB Type-C port, it can support power delivery of up to 100W.
Therefore, having a USB Type-C port does not necessarily mean it supports USB PD.
♦Is the USB Type-C connector mandatory for the USB 3.1 Gen 1 or Gen 2 specifications? Is USB Type-C equivalent to USB 3.0/3.1?
■ Currently, we can use traditional Type-A or Type-B connectors to support Gen 1 and Gen 2 specifications. The USB Type-C specification is a new interface certification specification released by the USB Implementers Forum (USB-IF). It supports up to 100W power delivery and reversible insertion. All products that support the USB 3.1 Gen 1 or Gen 2 specifications can use the USB Type-C connector.
So, our answer is: the USB Type-C specification is independent of the USB 3.1 Gen 1 or Gen 2 specifications.
♦What are DFP, UFP, and DRP?
■ A DFP (Downstream Facing Port) is a USB Type-C port on a host or hub that connects to a device, such as a power adapter.
■ An UFP (Upstream Facing Port) is a port on a device or hub that connects to a host or hub, such as a flash drive or portable hard drive.
■ A DRP (Dual Role Port) defines a port that can function as either a source or a sink on a USB Type-C port, such as a laptop.
The DRP mentioned above is different from a dual-role power port, which is a port that can act as both a power source (provider) and a sink (consumer). For example, a laptop's USB Type-C port supports DRP (Type-C Dual Role Power Port), which allows it to function as both a power source (when connecting to a portable hard drive or phone) and a sink (when connecting to a monitor or power adapter).
♦What is the Configuration Channel (CC) line? What is the maximum speed of the CC bus?
■CC bus is the data line used for USB-PD communication between the port and EMCA.
■The USB Type-C receptacle has two pins, CC1 and CC2. One of these pins is identified as the CC line based on the orientation of the USB Type-C connector.
■For USB Type-C plugs, the CC line is fixed.
■The CC line performs the following functions:
Detects USB Type-C plug orientation to establish USB data bus routing
Detects USB port connection from DFP to UFP
Establishes DFP and UFP roles between ports
Discovers and configures VBUS
Configures VCONN
Discovers and configures optional Alternate Mode and Accessory Mode
■ CC line bit rates range from 270 Kbps to 300 Kbps, with a nominal value of 300 Kbps.
