EIA-608 - Control Commands

Control Commands

Bits 15 and 7 are always odd parity bits. Bit 11 is always the channel bit.

For a preamble address code these are as follows: Bits 15 and 7 are parity bits. Bits 14 and 13 are always 0, bits 12 and 6 are always 1. Bits 10, 9, 8 and 5 indicate the row position. Bits 4, 3, 2 and 1 indicate the attribute of the text. Bit 0 indicates underline.

Row Preamble Standard Address and Style (Default Row 11 = 0,top rows 1-4 = 1-2,bottom rows 12-13 = 3) +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ preamble style |P|0|0|1|C|0|ROW| |P|1|N|0|STYLE|U| preamble address |P|0|0|1|C|0|ROW| |P|1|N|1|CURSR|U| +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ 15 8 7 0 15 8 7 0 Row Preamble Extended Address and Style (Bottom Rows 14-15 = 0,middle rows = 5-10 = 1-3) +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ preamble style |P|0|0|1|C|1|ROW| |P|1|N|0|STYLE|U| preamble address |P|0|0|1|C|1|ROW| |P|1|N|1|CURSR|U| +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ 15 8 7 0 15 8 7 0 P = odd parity ; C = extended caption toggle U = underline toggle ; N = next row down toggle (if style or cursor position not set, defaults are regular white text with black background at cursor = 0, cursor - multiple of 4) text style enumerations: {white=0,green,blue,cyan,red,yellow,magenta,italic white}

The row bits specify which of the fifteen screen rows should contain the caption text: row 11 (0000), 1 (0010), 2 (0011), 3, 4, 12, 13, 14, 15, 5, 6, 7, 8, 9, or 10 (1111).

The attributes bits allow 16 possibilities, which are: white (0000), green, blue, cyan, red, yellow, magenta, italics, indent 0, indent 4, indent 8, indent 12, indent 16, indent 20, indent 24, indent 28 (1111).

For a midrow code these are as follows: Bits 14, 13, 10, 9, 6 and 4 are always 0, bits 12, 8 and 5 are always 1. Bits 3, 2 and 1 form the color attribute (see the listing of attributes). Bit 0 indicates underline.

Mid Row Style Change (style remains in effect until either next change or end of row signaled by a control or preamble) +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ bg color |P|0|0|1|C|0|0|0| |P|0|1|0|COLOR|T| midrow style |P|0|0|1|C|0|0|1| |P|0|1|0|STYLE|U| +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ 15 8 7 0 15 8 7 0 +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ black bg |P|0|0|1|C|1|1|1| |P|0|1|0|1|1|0|1| black text |P|0|0|1|C|1|1|1| |P|0|1|0|1|1|1|U| +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ 15 8 7 0 15 8 7 0 P = odd parity ; C = extended caption toggle T = partially transparent ; U = underline toggle bg color enumerations: {white=0,green,blue,cyan,red,yellow,magenta,black}

For other control codes these are as follows: Bits 14, 13, 9, 6 and 4 are always 0, bits 12, 10 and 5 are always 1. Bit 8 chooses between line 21 and 284. Bits 3, 2, 1 and 0 identify the particular action.

The command bits allow 16 possibilities, which are: resume caption loading (0000), backspace (0001), delete to end of row (0100), roll-up captions 2-rows, roll-up captions 3 rows, roll-up captions 4-rows, flash on (0.25 seconds once per second), resume direct captioning, text restart, resume text display, erase displayed memory, carriage return, erase nondisplayed memory, end of caption (1111).

For tabs these are as follows: Bits 14, 13, 6, 4, 3, 2 are always 0, bits 12, 10, 9, 8, 5 are always 1. Bits 1 and 0 determine the number of tab offsets.