Basic HTML version of Foils prepared 5 February 98
| half-duplex - two-way transmission, one way at a time |
| full-duplex - independent, simultaneous two-way transmission in both directions |
| synchronous - both the sender and receiver are synchronized with a clock so receiver knows exactly where new characters begin |
| asynchronous - data is transmitted one character at a time, with intervals of varying lengths between transmittals. Start and stop bits at the beginning and end of each character |