So Omegix recently asked in the Synchronet Discussion group whether or not
a PETSCII (Commodore) terminal could be used to access his Synchronet BBS.
Now, the answer is "Yes". :-)
The major issues addressed:

- detecting a PETSCII terminal, solved by assigning specific (configurable):
  TCP ports to be used for incoming PETSCII connections, by default:
  port 64 is for 40-column PETSCII and port 128 is for 80-column PETSCII,
  but if the terminal sends a Telnet Window Size reply (e.g. SyncTERM), then
  either size terminal should fine on either port.
  The port numbers are configurable in the [BBS] section of your sbbs.ini
  file using the new keys: PET40Port (default value: 64) and PET80Port
  (default value: 128). Having these keys set doesn't make make the terminal
  server listen on that additional port - you'll need to add more
  IP:port combinations to one of Interfaces values, example:
    TelnetInterface=71.95.196.34,71.95.196.34:64,71.95.196.34:128
  And you don't have to use Telnet for the PETSCII connections - you could use
  RLogin or SSH instead (or in addition).

- support for terminal widths < 80 columns:
  This was achieved through a combination of text.dat changes (numerous),
  new Ctrl-A and @-codes and new optional terminal-width-specific menu files
  (e.g. text/menu/main.40col.asc)
  A side effect of these changes is actually better support for terminals
  *wider* than 80 columns as well!

- support for terminals that don't expand tabs to spaces (e.g. PETSCII):
  The terminal server now handles tab expansion with a run-time settable
  tab-size (default size: 8)

- conditional access based on PETSCII (or small) terminal use (or not):
  + New PETSCII ARS keyword (boolean)
  + New COLS and ROWS ARS keywords (for terminal width and height requirements)
  + New TERM (string) ARS keyword

New @-codes:
  - WORDWRAP, when placed at the top of a file, enables auto-wordwrap for
              lines longer than the terminal width
  - CENTER, the text following before an end of line will be displayed centered
            on the terminal (whatever the width, in columns)
  - CLEAR, like CLS, except it ignores (doesn't display) a CRLF that follows
  - COLS, current number of terminal columns (width)
  - ROWS, current number of terminal rows (height)
  - TERM, the auto-detected or reported terminal type (e.g. ANSI, TTY, etc.)
  - SYSONLY, toggles "echo" (display) off/back-on for non-sysops
            similar to the Ctrl-A( and ) codes, but more convenient to use
            (and PabloDraw won't strip the @-code from the file like it does
             with Ctrl-A codes it doesn't support)

New Ctrl-A codes:
  - \ conditional new-line/continuation when the terminal width is < 80 cols
      prints the new text.dat string LongLineContinuationPrefix

yesno() will now return true if passed a blank string.
noyes() will now return false if passed a blank string.
getstr()'s input length limiting based on terminal width is more broadly
           applied now (not just when using the K_LINE mode flag).

New JS bbs object method: menu_exists(<base_filename>) returns Boolean
New JS console object property: tabstop (Number)
New JS console object methods: getbyte() and putbyte() to recv/send raw byte
    value with (very little) interpretation/intervention by the terminal server
New JS console object method: creturn() - performs a carriage return
    (or equivalent)
New JS (and C) printfile() mode flag: P_TRUNCATE, causes long lines to be
    truncated, rather than displaying causing a line-wrap.

New text.dat strings:
  - NoAccessTerminal (for ARS check failures)
  - LongLineContinuationPrefix (for breaking long lines for 40col terminals)
  - Scanning (replaces a previously hard-coded "Scanning" string)
  - Done (replaces a previusly hard-coded "Done")
  - Scanned  (when finished scannning, clears the progress bar)