"' Digital Serial Interface "'( "'DSI "') is a data rate of 1200 baud, 1 start bit, 8 data bits ( dimming value ), 4 stop bits, and is the basis of the more sophisticated protocol Digital Addressable Lighting Interface ( DALI ).
42.
Each character is sent as a logic low start bit, a configurable number of data bits ( usually 8, but users can choose 5 to 8 or 9 bits depending on which UART is in use ), an optional parity bit if the number of bits per character chosen is not 9 bits, and one or more logic high stop bits.
43.
A common set-up of an asynchronous serial connection would be 9600-8-N-1 ( 9, 600 bit / s, 8 bits per character, no parity and 1 stop bit )-a total of 10 bits transmitted to send one 8 bit character ( one start bit, the 8 bits making up the byte transmitted and one stop bit ).
44.
Normally high, a device can indicate a transition on an ISA-compatible DRQ line by sending a 6-bit request : a 0 start bit, the 3-bit DMA channel number ( most significant bit-first ), one bit of new request level ( almost always 1, indicating that a DMA transfer is requested ), and a final 1 stop bit.
45.
For example, code 22, " synchronous idle " ( SYN ), was originally sent by synchronous modems ( which have to send data constantly ) when there was no actual data to send . ( Modern systems typically use a start bit to announce the beginning of a transmitted word & mdash; this is a feature of " asynchronous " communication . " Synchronous " communication links were more often seen with mainframes, where they were typically run over corporate leased lines to connect a mainframe to another mainframe or perhaps a minicomputer .)
46.
Each characters comprises a start bit at L state, 8 data bits, 1 parity bit, followed ( absent error ) by a delay at the H state ( a high voltage on I / O ) such that the leading edge of characters in the ATR is at least 12 ETU, with amaximum designated Waiting Time WT & # 8239; = & # 8239; 9 & # 8239; 600 ETU during the whole ATR ( Eurocard MasterCard Visa specifications add that the reader should tolerate 10 & # 8239; 800 ETU, that is 5 % more ).
