"HUB75" refers to the 16 pin connector and specific structure of the square wave signals it's expecting (row order, pixel order, etc). This particular sign app

"HUB75" refers to the 16 pin connector and specific structure of the square wave signals it's expecting (row order, pixel order, etc). This particular sign appears to use a 4mm pitch (space between each R/G/B led), indoor-level brightness SMD leds, and modules that are 32x64 pixels, like this one on AliExpress: https://www.aliexpress.us/item/2251832064290423.html?spm=a2g0o.productlist.main.1.818879c9LEceTp https://www.aliexpress.us/item/2251832064290423.html?spm=a2g... ( ~$8 + ~$9 shipping to the US for single qty). There are various "HUB75" panels of different pitch, brightness, LED type, matrix size, etc. Also, there's variations like "HUB75E" with 5 address lines instead of 4. Address lines are typically A/B/C, A/B/C/D, or A/B/C/D/E. And there's also "HUB08", "HUB12" and other standards.