I've often been asked about power supply compatibility, so following is a summary of the attributes to consider when swapping or replacing adapters. I've also seen people throw out equipment just because these cheap and relatively unreliable power bricks fail, while getting a replacement DC adapter would be much cheaper and easier.

Attribute	Symbol	Compatibility notes
voltage	V	Must match
current	A	PSU can be larger
polarity	⊖──❨●──⊕	Usually needs to match
type	𝌃	Regulated PSU can supply any device

DC power supply notes

• Thinner and longer wires have a larger voltage drop, so you may need to get a slightly higher voltage DC adapter if using running over ethernet for example
• Unless there is a problem with the equipment it shouldn't draw any more current than it requires, so an adapter with a larger output current rating is fine
• The polarity symbol is intuitive enough, with the center part of the symbol representing the connector. Some equipment can support mixed polarity supplies, but that's not usual
• The symbol shown above for the type of PSU, represents the most common unregulated DC supply. If equipment expects a regulated supply it will indicate that as a single solid horizontal line
• The end connector size can vary, so be sure to match that also
• Note there are universal PSUs available with switchable voltages, and adapters for various connector sizes