Black Box SW023A-FFF Manual ABC Switch 25-Pin DB25 Parallel Serial 1x2 Sharing

Black Box SW023A-FFF Manual ABC Switch 25-Pin DB25 Parallel Serial 1x2 Sharing

The Black Box SW023A-FFF is a manual ABC data transfer switch that allows one 25-pin parallel or serial peripheral — such as a printer, plotter, or serial device — to be shared between two host computers or devices. Switching between hosts is accomplished via the front-panel toggle with no software, drivers, or external power required.

Specifications & What's Included

• Model: Black Box SW023A-FFF
• Switch type: Manual ABC (no power required)
• Configuration: 1-to-2 (one peripheral shared between two hosts)
• Connector type: DB25 (25-pin), three ports — labeled A, B, and C on rear panel
• Interface: Parallel and/or Serial (DB25)
• Front panel: Manual toggle switch, Master/Alternate and A/B position labels, Loop 1 Odd Registers plate
• Enclosure: Compact black metal desktop case
• Country of manufacture: USA (per bottom label)
• Unit only — no cables included

Applications

Manual ABC switches like the SW023A-FFF were a common solution in the 1980s and 1990s for sharing parallel printers, plotters, and RS-232 serial devices among multiple computers without the need for a network or software. A single DB25 peripheral — most often a dot-matrix or laser printer, external modem, or serial instrument — could be connected to port C on the rear, while two host machines connected to ports A and B. The operator selects which host has access by toggling the front switch. Black Box Corporation was a major supplier of these manual data switches and peripheral sharing devices, and the SW023A-FFF was widely used in small offices, labs, and workstation environments of that era. Legacy systems still running parallel-port peripherals, older scientific instruments with RS-232 interfaces, and serial industrial equipment continue to make this type of passive manual switch useful today for anyone managing older hardware.