Brown box
Brown box turns up in 2 fields: electronics, telecom & it. Here is what it means to the people in each one.
Brown box in electronics
A bare-bones hardware component sold without retail packaging or accessories.
A piece of electronic hardware shipped in plain, unbranded cardboard packaging rather than a colorful retail box. These units typically include only the essential component in an anti-static bag, omitting manuals, driver discs, extra cables, or promotional materials. System integrators and repair shops buy them in bulk to cut costs and reduce waste when the extra accessories are unnecessary.
"I ordered a dozen brown box motherboards for the lab upgrade since we already have plenty of cables and standoffs."
Brown box in telecom & it
A historic phreaking device used to bridge two telephone lines into a makeshift party line.
A brown box was a simple electronic circuit built by telephone enthusiasts to connect two separate phone lines. When someone called either line, both phones would ring, and answering either would bridge the audio. Phreaks used them to create unauthorized conference calls or hide their location by routing calls through an intermediate drop.
"He wired up a brown box in the basement so we could conference in the whole group without the operator knowing."