Classic Computer Magazine Archive ANTIC VOL. 2, NO. 2 / MAY 1983

Tele Chess

by Thomas McNamee and Pete Goodeye

Some avid chess players transmit moves by mail. Others have probably used carrier pigeons, Saint Bernards, and secret agents. We believe that this program is the first time that truly-interactive chess has been played on ATARIs hooked up for data communication.

This collaborative coup began w~th the colorful game board and housekeeping program submitted by Thomas McNamee. He designed the black and red playing area, the blue and greenchessmen, and the method of moving them with a cursor controlled by a joystick. He did not program the computer to play, but only to support two human players.

It dawned on us that it would be appropriate for this, our communications issue, to further develop the game so that the players could be remote and play each other over the phone lines. This meant that somehow each player would have the current board displayed, and that the consequences of moves would be transmitted back and forth.

Pete Goodeve, an inveterate programmer recently intrigued by the communications potential of the ATARI, undertook the project and added routines to transmit the moves, as well as text messages between the players. He tested and refined the program with the help of David Duberman, ANTIC's Technical Assistant, who wrote up the instructions for the connections and other transmission details. His work has been merged with McNamee's instructions on playing the game.

Tele-Chess is not a polished product, and users may encounter problems we did not. Still, the program should work between two ATARIs connected by modems over the phone. If you do have problems, your own efforts to solve them will be appreciated, and your solutions will be welcome here. We will write a follow-up article summarizing enhancements and your other experiences. Please send this information by mail, since we are not staffed well enough to handle the high volume of telephone inquiries this project is likely to generate. --ANTIC ED

This program allows two players to play chess with each other over a remote phone connection using their ATARI computers. Both computers must be equipped with a minimum of 16K RAM and a modem (with or without the 850 Interface, as required by the modem). A joystick for each player is necessary for game play.

IMPORTANT: read through this entire article before attempting any of the steps.

Each player must enter the BASIC listing. Do this by typing it in. Use TYPO to verify correctness. Save the program to tape or disk. Or, once entered by one player, the program can be transmitted by phone to the other party. Enter by hand if your data-communications skills are not yet that sharp.

Note that the program itself includes a checksum feature for the DATA statements. If you get an "INCORRECT DATA STATEMENT" message, one of the DATA lines has not been entered properly.

Before you RUN the program, make sure your 850 interface is turned on and the RS-232 handler is booted. For disk systems, an RS-232 handler is part of the AUTORUN.SYS file included in your Atari DOS Master Disk, and it loads automatically when booted. If your system is cassettebased, the RS-232 handler boots itself if the 850 is turned on before the computer. When the program is up and running, it should initialize, display the chessboard with all the pieces, and print a menu at the bottom of the screen.

At the top of the screen, the sides are shown as "BLACK" and "WHITE" (really blue and green). An arrow in the center of this line shows whose turn it is. The cursor is displayed as a solid pink square, almost covering a chessboard - square. The cursor is moved with a joystick attached to Port One. As the cursor moves, it will pass over the board and under the playing pieces.

In order to move pieces, you must be on-line to another computer running the same program; but before you establish the connection, both players must LOAD and RUN the program on their ATARIs. Then, by prior agreement, one person sets his modem to originate and the other sets his to answer mode, and both should be set to full-duplex.

Establish voice contact by phone, determine who will move first, and then attach the phones to the modems. The modem in originate mode should be hooked up first. If you don't have an originate / answer switch on your modem, the modem can probably do both (e.g. Anchor Signalman direct-connect modem).

Upon attaching the modems, one of you should attempt to send a message via the keyboard to determine whether contact has been established. If you press any key, you'll see an INPUT prompt (?) appear. Continue typing, press RETURN after finishing the message, and it will be transmitted. Don't attempt to send a single message of over 30 characters, or the remainder will be truncated. Messages may be sent in this way at any time during the game, even if your opponent is moving a piece.

To move a piece, place the cursor under the piece and press the fire button. The cursor will turn white, indicating a move is in progress. Move the cursor to the destination square, and press the button again. The piece will relocate to that square. The move, though not the cursor, wili be transmitted to your opponent's screen.

No check is made in this program For illegal chess moves. If you change your mind about moving a piece after it has been selected, move the cursor back to the original square and press the button. The cursor will turn pink again?, and it will still be your move.

Both players alternate moves using a joystick in Port One. When a move is completed, the arrow at top changes on both screens, pointing to the other player. Captures are made when the destination square of a piece already contains an enemy.piece. The captured piece is removed from the board(s), and placed off to the side belonging to the captor. You cannot capture your own piece.

The cursor is limited to the board areas only, except for the bottom row, where the letters S, B, G and F are printed. These are playing options, and are described in the menu at the bottom of the screen. This menu scrolls up and out of sight when you transmit text messages. To select an .option, place the cursor over one of these letters and press the button. The actions of these options are as follows:

S--Set-up Mode. This allows either player to set any piece at any position on the board, or to remove any piece. The cursor turns dark blue when in this mode. Move the cursor to the destination square, and press the fire button to cycle through the pieces until the one you want appears on that square. Note that one of these selections is a blank space, used for removing pieces from the board. If one player attempts this option while online, it's important that the other player not attempt a move at the same time, or the board could become out of sync. Note that the arrow at top does not flip after a Set-up to indicate a new move. It's best not to attempt a Set-up during a game until you've become fairly familiar with the program. To return to the game, move the cursor to the "G" option and press the button. The cursor will return to pink.

B--Begin New Game. Clears your board, but not your opponent's! Also clears the capture areas, and puts all pieces back in their original positions. If this option is selected, make sure both players use it simultaneously. Otherwise the boards will not match and moves will be impossible.

G--Game Mode. Both boards default to Game Mode, so "G" is only used to leave the Set-up Mode for return to normal play.

P--Pass. Game moves are transmitted automatically. If you want to "pass," i.e. not move this turn, type "Pass" and RETURN. Then each player selects "P" to flip the turnindicating arrow on their own board.

It's possible, and probably will be necessary, occasionally to break out of data-transmission mode to communicate verbally. First, each player should depress the space bar to invoke the input prompt. Disconnect the phone from the modem and speak normally. When you wish to return to the game, replace the phone in the modem (or switch from Voice back to Data on a direct-connect modem). At this point, both players should press RETURN. If one cannot (it does happen), the other probably will be able to, whereupon data communication will be re-established. If neither keyboard responds (possible but not likely), it will be necessary for both to RUN the program again.

If you have a newer 850 interface, you'll be able to BREAK and RUN again. Otherwise, you'll find your BREAK key is disabled and it will be necessary to reboot. RESET at this point will probably cause a system crash, also necessitating rebooting.