Accessing La Cueva BBS in Mexico in 1993

My main computer in 1993 was a Zilog Z280-based homebrew computer with 512 KB of RAM. It had a VGA card for display, a 3 1/2" floppy disk drive, and connectors for serial ports, and printer port.

I got a discarded Hayes modem with the amazing speed of 2400 bauds. For some reason it didn't had the top of the case, it was a bulky black long box. But it was easy to interface, and I used a lot of time to write a serial terminal program.

The Internet didn't existed yet, and the information about serial protocols and AT commands came from books, the same as the ANSI escape sequences. The serial protocol was RS-232C, and relatively easy, just take a letter from the input and display it on the screen, take any letter from the keyboard and send it back. I didn't even worry about flow-control, because the UART was set to 2400 bauds, the same as the modem. Hardware flow-control using RTS/CTS pins became common when the 14400 bauds modem appeared, as the UART would need to be set at 19200 bauds (faster than the modem)

The AT commands also were relatively simple. For example, ATDT5551234 means to dial the number 5551234 using tones. Although in Mexico in 1993 we still used ATDP5551234 to dial using pulses.

The ANSI escape sequences are formed by the Esc character (0x1b) followed by the opening square bracket [ some numbers, and a letter that signalled the command. For example, Esc [2J mean to erase the screen. Esc C moved the cursor to the right, and ESC[0;35m set a magenta color for the letters. I implemented all these escape sequences on my terminal program.

However (and luckily for this article), the book and the real usage differed slightly. So some BBS would look weird. To solve this, I implemented a capture buffer in my terminal program. The Z280 allows for MMU access to a 64K area, so I programmed it to save every received byte sequentially. When the display differed from what I expected, I would give a look to the escape sequences, and most of times found a small deviation that I could correct in my program.

Almost nothing was saved from that time, but for some reason in one of my modem sessions, I saved a whole 64K buffer of my activity calling La Cueva BBS. Just a file CUEVA.TXT I found on one of my old floppy disks, saved after February 11, 1993 (I know this because the BBS displayed the last logon time), and the session was from 9:30pm to 9:47pm, also reported by the BBS. You can see I downloaded a file, but the data for it wasn't captured as only the displayed data was captured. You can even see trash when the phone line failed.

One thing that couldn't be preserved was the keystroke timing, so the screens change very fast. But probably I took several seconds to read each screen.

There were also other BBS at the time like Catarsys. I think La Cueva BBS disappeared by 1994 or 1995, along all the remaining BBS. The sysop just put a temporary message, and soon the phone ceased to answer.

I made a Javascript code from the CUEVA.TXT file, and this data file is feed to an adapted jsTerm by Peter Nitsch with the speed of 2400 bauds. I didn't noticed before that jsTerm couldn't scroll because the security policy for the font "taints" the canvas, so I had to modify my .htaccess file to allow it. Also the updated jsTerm has been updated in my transputer git.

<Files "ansilove_font_pc_80x25.png">
  Header set Access-Control-Allow-Origin "https://nanochess.org"
  Header set Access-Control-Allow-Methods: "GET"
  Header set Access-Control-Allow-Headers "Content-Type, Authorization"
</Files>
        

I'm glad I found this file, because watching it again brought memories, and surprisingly enough some of my friends didn't had an idea this BBS existed. Enjoy it!