Serial transfer refers to the process of connecting a digital camera to a computer via a serial port-commonly called the COM port on PCs or the Printer/Modem port on older Apple Macs-to download images. Data is transmitted sequentially, one bit at a time, which makes the process slower compared to modern transfer methods like USB or FireWire.
Although largely replaced by faster interfaces today, serial transfer was an essential method for early digital photography workflows, allowing photographers to move images from their cameras to computers for editing, storage, and printing. Understanding serial transfer is helpful when working with legacy digital cameras or archival digital workflows.