This is MAX7219 Based Serial 8-Digit 7 Segment LED Display Module. Also Called LED Tube Display. It has an integrated serial input / output common-cathode display drivers, which connects the microprocessor and 8 digit 7-segment digital LED display.
A convenient four-wire serial interface can connect all common microprocessor. Each data can be addressed in the update without rewriting all displays. MAX7219 also allows the user to select each data encoding or no coding.
The display also has a 150µA low-power shutdown mode, analog and digital brightness control, a scan-limit register allows the user to display 1-8 bit data.
(Serial Out – For Cascading or chaining)