asynchronous communication interface adapter (ACIA)

An Asynchronous CommunicationInterfaceAdapter (ASIA) is a converter that converts bit-parallel data to serial data; it is a parallel-to-serial converter or, conversely, a serial-to- parallel converter. The asynchronous data is present in parallel at the input of the parallel-serial converter and is available in serial at the output. Technically, parallel-serial converters are formed by shift registers.