NonUSB

NonUSB is a descriptive label used to denote devices, peripherals, interfaces, or connectors that do not use the Universal Serial Bus (USB) standard for data transfer or power. It is not an official standard; rather, it groups technologies by what they lack rather than what they share.

Common non-USB interfaces include serial connections such as RS-232 and RS-485, parallel ports, SCSI, IDE (PATA), SATA for storage devices, PCI Express, FireWire (IEEE 1394), and Ethernet. These interfaces rely on dedicated buses or protocols separate from USB and are often found in legacy equipment, industrial systems, or specialized hardware.

Non-USB solutions are chosen for several reasons, including lower latency, greater tolerance to electrical noise, simplicity in embedded environments, or where USB’s power and plug rules are undesirable. In modern product lines, manufacturers may provide both USB and non-USB options or offer adapters to bridge between USB and other interfaces (for example USB-to-serial or USB-to-Ethernet bridges).

Overall, non-USB describes a broad, informal category rather than a single standard, reflecting the long-running coexistence of multiple data-busing technologies alongside USB.