BBS Graphics Mode
BBS Operation - Graphics Mode
Graphics Mode Design
When a caller first logs on, the system determines the type of terminal being used through the Backspace/DEL test. Commodore graphics terminals send a CHR$(20) code when the DEL key is pressed, while ANSI and ASCII terminals typically send CHR$(8) or CHR$(127).
If the caller is using ANSI or ASCII, the system will ask whether ANSI graphics are supported. If the caller answers "Y", full ANSI color and graphic translation will be enabled. If "N" is selected, the caller will then be asked whether their terminal requires line feeds appended to carriage returns. This accommodates ASCII terminals that automatically add line feeds.
Commodore Graphics Mode
Commodore graphics terminals experience the system as originally designed, with full PETSCII graphics and color control. This capability is the reason the system was named Color 64, as it was among the first BBS systems to fully support advanced Commodore terminal programs such as CCGMS.
Background color changes are supported using the CTRL/B sequence. When a color key is pressed immediately after CTRL/B, the background color changes accordingly. On Commodore 128 80-column terminals, CTRL/B enables underline mode instead, so background changes do not function the same way. Color 64 properly passes through 80-column control codes such as underline and flashing attributes when appropriate.
The ASCII and ANSI translation routines are handled in part by machine language routines located beginning at memory area $C044+ (via calls to $FFD5).
ASCII Mode
When a caller connects using a plain ASCII terminal, Color 64 performs the best possible character translation. PETSCII graphic characters are converted to readable ASCII equivalents, and the system respects the current uppercase/lowercase state of the display.
| Commodore Graphics (PETSCII) | ASCII Translation by Color 64 |
|---|---|
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ANSI Graphics Mode
ANSI callers receive a high-quality conversion of Commodore graphics and color. Color 64 supports 15 ANSI foreground colors. Dark grey may not function properly on some ANSI terminals and is therefore translated to medium grey when necessary.
| Commodore Graphics (PETSCII) | ANSI Translation by Color 64 |
|---|---|
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ANSI users should configure their terminal with a default black background for best compatibility. Additionally, the terminal should not automatically append a carriage return after a line feed, since the line feed character is used by the system as a cursor-down control in ANSI mode.
Because many ANSI terminals support only eight background colors, bold color variants may not display correctly in reverse mode. As a result, certain graphic translations may appear slightly different than their Commodore equivalents.
ANSI callers may manually change the active cursor color by pressing the ESC key followed by two digits. The first digit controls bold mode (0 = normal, 1 = bright), and the second digit selects the ANSI color (0–7). This provides access to the full range of color combinations available to Commodore graphics users.
Next Section: The User Application