KVM switch and data transmission method

A data transmission method is used between a first computer, a second computer, an input interface device, a display device, and a KVM switch. The first computer, the second computer, the input interface device and the display device are coupled to the KVM switch. The data transmission method includes: when the KVM switch receives a first command from the input interface device, the KVM switch receives a screenshot from the first computer in response to the first command; the KVM switch recognizes the screenshot and generates text information correspondingly; and when the KVM switch receives a second command from the input interface device, the KVM switch transmits the text information to the second computer in response to the second command, and displays the text information on the display device.