Uninformed: Informative Information for the Uninformed

Vol 1» 2005.May

Synchronous Cards

Synchronous protocols are usually used with memory cards mainly to reduce cost (since the card doesn't require an internal clock) and because usually memory cards don't require much logic and are used for simple applications. Asynchronous cards on the other hand have an internal clock and can communicate with the reader at a fixed rate across the I/O line (usually 9600 baud), asynchronous cards are usually used with processor cards where more interaction is required (see Phrack 62-15).