Can you carry laptop on your flight?

When you buy a new laptop, your lithium battery might be shipped in a plastic bag with UN 3480 label on it (see Figure 1).  What does it mean?  Can you carry your laptop (lithium battery included) on your flight?

Figure 1.  UN 3480, Lithium ion batteries (shipped by themselves)

Types of Lithium Batteries

Lithium batteries are dangerous goods and, as such, require special packaging for transportation.

All domestic and international shipments containing lithium batteries are subject to transport regulations on hazardous goods according to ADR (truck)/RID (rail), ADN, IMDG, ICAO / IATA Regulations.

Lithium batteries are basically distinguished as:^[2]

• Lithium metal batteries 
• In general are non rechargable and contain metallic lithium. 
• Lithium ion batteries
• Don´t contain metallic anymore, but a lithium compound (lithium oxide) and they are rechargable. Often they are called accumulators.

What's UN 3480?

The United Nations (UN) have developed a classification system for dangerous goods. They will be assigned to classes according to their dangerous properties. Another order scheme are the UN numbers, i.e. each dangerous goods must be assigned to a four-digit number, the so called UN number. 

If a new laptop is shipped to you, your new standalone lithium battery needs to be labeled with UN 3480 following the following packaging regulations:

• Batteries must be placed in inner packaging that completely enclose the battery, batteries must be protected so as to prevent short circuits.
• 30 kg gross weight per packaging
• Strong outer packaging, e.g., fiberboard box (drop test passed: content shall not be damaged or shifted)

For lithium batteries at first you have the following UN numbers:^[2]

UN 3090	LITHIUM METAL BATTERIES (including lithium alloy batteries)
UN 3091	LITHIUM METAL BATTERIES CONTAINED IN EQUIPMENT (including lithium alloy batteries)
UN 3091	LITHIUM METAL BATTERIES PACKED WITH EQUIPMENT (including lithium alloy batteries)
UN 3480	LITHIUM ION BATTERIES (including lithium polymer batteries)
UN 3481	LITHIUM ION BATTERIES CONTAINED IN EQUIPMENT (including lithium polymer batteries)
UN 3481	LITHIUM ION BATTERIES PACKED WITH EQUIPMENT (including lithium polymer batteries)

Additionally there is for vehicles the UN number UN 3171 (for electrically powered vehicles only) and UN 3166 for hybrid vehicles.

Can you carry laptop on your flight?

The short answer is:^[3]

Passengers may carry their battery-powered devices (incl. laptop) and spare batteries in their carry-on bags. 

The simple reason for doing this is to protect your own safety by preventing the short circuit of lithium batteries during your flight.  When lithium batteries fail to operate safely or are damaged, they may present a fire and/or explosion hazard.^[4]

References

1. How to ship lithium batteries by air—in 2020 and beyond
2. Lithium Battery Service (FAQ)
3. Can I bring my laptop on my flight? And other tips for traveling with tech
4. Preventing Fire and/or Explosion Injury from Small and Wearable Lithium Battery Powered Devices
5. Flying with batteries and electronics restrictions

USB — Knowing the Basics of Universal Serial Bus

Universal Serial Bus (USB) is an industry standard that establishes specifications for cables and connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad variety of USB hardware exists, including eleven different connectors, of which USB-C is the most recent.

Figure 1.  Lenovo T495

Figure 2.  Lenovo ports layout

Always On USB 3.1 connector (Figure 2.9)

• There is a feature called "Always On USB" which allows devices connected to the laptop via USB to be powered over USB even when the Operating system (Windows 10 in my case) shuts down.

USB 2 and USB 3 Compatibility

• USB 3.0 backwards is compatible—meaning it's designed to work with older USB versions including USB 2.0 and USB 1.1. 
• You can plug a USB 2.0 device into a USB 3.0 port and it will always work, but it will only run at the speed of the USB 2.0 technology.
• USB 3.0 Flash Drives and card readers are backwards compatible with USB 2.0 and USB 1.1 ports. The USB 3.0 Flash Drive or card reader will work at the speed of the port, for example if you use a USB 3.0 Flash Drive in your USB 2.0 laptop, it will work at USB 2.0 speed.

USB Type C vs USB 3.1 Gen 2

• The USB Type C standard defines only the physical connector while the USB 3.1 Gen 2 standard applies only to the electrical signal. 
• USB 3.1 connector Gen 2 (Figure 2.18)
• Also referred to as SuperSpeed+
• USB-C connectors (USB 3.1 Gen2; Figure 2.20)
• USB-C is an industry-standard connector for transmitting both data and power on a single cable.
• The physical USB-C connector isn’t backwards compatible, but the underlying USB standard (could be USB 2.0 or 3.0) is.
• But that doesn’t mean you have to discard all your old peripherals. USB 3.1 is still backwards-compatible with older versions of USB, so you just need a physical adapter with a USB-C connector on one end and a larger, older-style USB port on the other end. 
• The USB-C connector looks similar to a micro USB connector at first glance, though it's more oval in shape and slightly thicker to accommodate its best feature: flippability. Like Lightning and MagSafe, the USB-C connector has no up or down orientation.
• Even if you get a computer with only USB Type-C ports, like Apple’s new MacBook, adapters and hubs will fill the gap.

Figure 3. USB Standards^[1]

USB Connectors

Sizes

• default—standard format intended for desktop or portable equipment
• mini—intended for mobile equipment
• micro—intended for low-profile mobile equipment such as mobile phones and tablets

Speeds (Figure 3)

• USB 2.0—Low, Full, High Speed
• USB 3.1 Gen 1—SuperSpeed (or SS in Figure 3)
• USB 3.1 Gen 2—SuperSpeed+ (or SS+ in Figure 3)

Shape (Figure 4)

• Type-A
• Type-B
• Micro-B
• Type-C

Figure 5.  USB Shapes

Figure 6. USB Plug Types (SS: SuperSpeed)

Figure 7. USB port symbols

References

1. USB Type C and USB 3.1 Gen 2 – Clarifying the Connection
2. USB Hardware (Wikipedia)
3. What Is USB-C? An Explainer
4. USB Implementers Forum (USB-IF)
5. Levnovo USB-C Laptop Power Bank 14000 mAh
• Power delivery (PD) is lower than 65w
6. The Best USB and USB-C Hubs
7. USB Type-C Explained: What is USB-C and Why You’ll Want it
• The USB PD specification supported by USB-C ups this power delivery to 100 watts. 
• It’s bi-directional, so a device can either send or receive power. And this power can be transferred at the same time the device is transmitting data across the connection. 
• This kind of power delivery could even let you charge a laptop, which usually requires up to about 60 watts.
8. USB Power Delivery 2.0 vs 3.0
• USB PD 3.0 ensures backwards compatibility with USB PD 2.0. All USB PD 3.0 sources and sinks are required to fully interoperate with USB PD 2.0 sources and sinks. This requirement is enforced by requiring all USB PD 3.0 devices to pass USB PD 2.0 compliance tests. In fact, from the USB Implementers Forum (IF) point of view, there are only USB PD products. The USB-IF does not distinguish between USB PD 2.0 products and USB PD 3.0 products when issuing USB logo certification.
9. Lenovo T495 Hardware Maintenance Manual
10. ThinkPad T495 Spec (pdf)
• Standard Ports
• 1x USB 3.1 Gen 1 (Always On)
• 1x USB 3.1 Gen 2
• 2x USB-C 3.1 Gen 2 (support data, PD and DP 1.4)
11. ThinkPad T495 User Guide (pdf)
• USB-C connectors (USB 3.1 Gen2)
• Charge your computer.
• Charge USB-C compatible devices with the output voltage and current of 5 V and 1.5 A.
• Transfer data at USB 3.1 speed, up to 10 Gbps.
• Connect to an external display:
• USB-C to VGA: 1900 x 1200 pixels, 60 Hz
• USB-C to DP: 3840 x 2160 pixels, 60 Hz
• Connect to USB-C accessories to help expand your computer functionality. To purchase USB-C accessories, go to https://www.lenovo.com/accessories.
• Supply power to another computer using P-to-P (Peer to Peer) 2.0 charging function. See “Use P-to-P 2.0 charging function” on page 25.