A USB adapter is a device that can plug into a USB port on a laptop and provide wireless connectivity to a network. A USB adapter can support different wireless standards, such as 802.11a, 802.11b, 802.11g, 802.11n, or 802.11ac. A USB adapter can also support different wireless frequencies, such as 2.4 GHz or 5 GHz.

In this case, the user with an older laptop may not be able to connect to the office network after new access points were installed because the laptop’s built-in wireless card does not support the same wireless standard or frequency as the new access points. For example, if the new access points use 802.11ac and 5 GHz, and the laptop’s wireless card only supports 802.11g and 2.4 GHz, the laptop will not be able to communicate with the access points.

To quickly resolve this issue, the user should connect a new USB adapter that supports the same wireless standard and frequency as the new access points. This way, the user can bypass the laptop’s wireless card and use the USB adapter to connect to the office network wirelessly.