How does the keyboard wedge work?
The keyboard wedge interface is a chain, like daisy-chaining (e.g. SCSI), or serial pass-thru. It does not require a terminator or terminating device at the end of the chain (the farthest device from the keyboard port). The last device on the chain can be a keyboard wedge device or a standard AT keyboard. This type of keyboard can only exist as the last device on the chain. Keyboard wedge devices are generally input devices such as keyboards, bar code scanners, and magnetic stripe readers (MSRs). Each device acts like a keyboard and sends the same keyboard scan codes to the computer. Because of this, no driver is required; everything is controlled by hardware. If any device on the chain is locked, such as a Posiflex keyboard on L0, that device and all devices after it on the chain (farther from the computer) will be disabled. To use these devices set the key position away from L0 (LP or L1-L4). See also How does the serial pass-thru work?
