Classic Computer Magazine Archive ANTIC VOL. 3, NO. 3 / JULY 1984


An Atari, a cable and a lap-size computer



This article discusses the transfer of data between "notebook" computers and Atari personal computers. An 850 Interface is required. For best results, you should use a commercial or machine-language terminal program that is capable of data transfer at rates up 9600 baud for the Atari.

Notebook computers are the latest rage in the microcomputer world. These book- sized machines are very light and portable, yet feature large amounts of RAM, full-sized keyboards, built-in software, and much more. Because they hold every character in "non-volatile" memory, there is little drain on the computers' batteries. This keeps memory from being erased when the machines are switched off.

With a notebook computer, you can write or program anywhere -- on a bus or plane, while sitting in the park, or even lying in bed. Later, you can transfer the file to your Atari to add some finishing touches. You can then print out the text or save it to disk or cassette. At this time, there are three major notebook computers that retail for approximately $795; Radio Shack's Model 100, the NEC PC-8201A and the Epson HX-20.

It is already clear that many computer owners are buying one of these notebook models to use with their main machine. This article explains how to transfer files between a notebook computer and an Atari. The process is slightly different for each combination of machines, but the guiding principles are similar.


The most obvious way to connect two computers is by phone line, using a modem on each end, supported by the appropriate terminal software. Of course, this requires two modems and two phone lines at the same location - a costly arrangement in the home environment. A direct connection is much more desirable.


All notebook computers have an RS-232C connector. RS-232C refers to an industry standard established to govern data communications. It determines the functions of the essential pins in a 25-pin connector intended for communications use. Table I identifies the eight RS-232C pin assignments involved in the connection we want to make. The Atari 850 Interface has four 9-pin serial ports. Port I (850SP1) is the most fully configured, and is the one we will use.

Note that both ports are female, so you will need a 25-pin male connector (DE-25), a 9-pin male connector (DR-9), and several feet of cable with at least eight wires in it. The pins are numbered from top to bottom and right to left as you face the female plugs, and left to right as you face the male plugs. Be careful to properly identify the male pins and their corresponding wires while wiring.

Note that the significant differences involve pins 2, 3, 6 and 20 on the RS-232 side and pins 1, 3, 4 and 6 on the Interface side. Send goes to Receive, and vice versa. DTR goes to DSR and vice versa. Refer to the owner's manual of your non-Atari computer to verify these pin assignments in your particular case.

If you make this cable, you'll have what's referred to as a "null modem." It differs from the standard modem cable by virtue of the wiring crossover between pins 2 and 3 described above. Be sure to verify the wiring with an ohm meter before using it. Turn off each computer and the interface before connecting the cable.

Software takes care of everything else. On the Atari side, we use TeleTari (Tronix), but AMODEM, a public domain program printed in this issue, will serve as well. Other communications programs should also work, but we have not tested them. As for the notebook computers, each has built-in communications software. The NEC and Radio Shack Model 100 feature TELCOM, and the Epson offers SkiModem.


The details vary, but in all cases yo must complete the following steps:

-- Connect the two computers with the null-modem cable.
-- Power-up the computers and interface.
-- Load the appropriate communication program into the Atari.
-- Call up the communications program in the portable.
-- Adjust the status of each communications program to match the other.
-- Set one of the computers to send (upload) and the other to receive (download).
-- Transfer the file from one computer to the other.
-- Save (or otherwise use) the received file.

"Translation" is a term you hear often in the context of Atari communications. It refers to several idiosyncrasies of the Atari that must be accommodated before communication with non-Atari computers is possible. "Light translation" converts the Atari end-of-line ([RETURN]) from decimal 155 to the standard ASCII value of 13 or vice versa. See the 850 Interface manual for further details.

The instructions for your terminal programs will guide you through the further formalities. The following are examples of our experiences.


Load TeleTari on the Atari and set the status for 4800 baud and no translation. The rest of the default parameters are fine. Set up the Skimodem program according to instructions. Use a value of 246 for x and 104 for y. If your baud rate of transfer is 300, use a value of 40 for y. Once Skimodem is running, the two computers can "talk" directly to each other; whatever you type on the Epson appears on the Atari's display, and vice versa. As long as each modem program is saving transmissions to its buffer (a special holding area in memory), you can save everything to disk or cassette later. If you use this method extensively, use 300 baud -- we lost too many characters at 4800 baud.

To send text files from the Epson to the Atari, load your document into the SkiWriter program's memory before you load and execute Skimodem. We had no problem with transfers at 4800 baud. The main hitch with this technique is that you lose control characters (most notably linefeeds). Once you have the document in your word processor on the Atari, go through and add linefeeds and other control characters wherever this is necessary. It isn't much fun, but it beats retyping. If you want to write BASIC programs for the Atari on the Epson, first reset some of the parameters on the Atari terminal program. Use 300 baud and light translation (to allow carriage returns to be translated from ASCII to the internal Atari code, ATASCII. Then type the following sequence of commands on the Epson:

OPEN "0" #1, "COMO:(28N1D)"

These commands should be executed from within the program area holding the BASIC program you wish to transfer. The first two lines set the Epson's RS-232 port to match the Atari's terminal program; the third (to which you may add line ranges) actually list the file to the Atari.


Connect the computers with your cable. Then load and run your Atari terminal program. Set it to 9600 baud, full-duplex, and use default settings for the other parameters.

Next, select the TELCOM program from the Model 100's menu. The status line in the screens upper-left corner should read:

87I1E, 10 pps

This tells TELCOM that you want to commumcate at 3600 baud with seven-bit word length, no parity, one stop bit, XON/XOFF enabled, and 10 pulses per second for auto-dialing. If TELCOM doesn't show these settings, press [F3] and type in the above string, followed by [ENTER] in response to the STATUS prompt. Now press [F4] to put TELCOM in terminal mode.


Set up your Atari terminal program to receive and activate the transmission. Next, press [F3] on the Model 100 to request Upload. TELCOM will then ask you for the name of the file you want to move. Type in the name, including the extender (e.g., MOVER.DO) and press [ENTER].

[TELCOM next prompts you for line width. Press [ENTER] without typing anything else; otherwise, TELCOM inserts a linefeed after each line. As soon as you do this, the highlighted word "UP" appears above [F3] and data transfer begins. You should see the text appear on your monitor screen as soon as the Atari receives it. You won't see the text on the Model 100 screen.

Every time the Model 100 sends a carriage return, the cursor writes over the current line without skipping down to the next. Even though you lose data on the screen, the Atari receives everything in the file. However, it will be necessary later to edit the text file on the Atari.


To transfer text from the NEC to the Atari, first create a text file with the NEC's TEXT program. Then enter TELCOM. Since TELCOM is set up for 9600 baud, you needn't change any of the parameters. Load TELETALK on the Atari with the 850 connected and turned on. Follow directions to change TELETALK's baud rate to 9600. If you use a terminal program that allows you to set translation, set it to light translation. On the NEC, press [F5] to enter TERM. Next, press [F4] for Upload. At the prompt, type in the name of the file you wish to transfer. Transfer begins automatically after you enter the file name (if the file exists), and the text appears on the Atari screen. To save the text to a disk file, press [START], then [S] for Save text, and then type in a file name after the prompt 'D:' and press [RETURN].


To transfer text from the Atari to the NEC, it's best to use a terminal program on the Atari that offers the light translation option. This converts Atari EOL(155) to ASCII EOL (13), so the Atari's EOL's won't show up as carats throughout the text file on the NEC. Unfortunately TELETALK doesn't let you change translation.

If you use TELETALK, set it for 9600 baud, and then go to the main menu and press [U] for Upload. Enter the file name at the prompt and wait for TELETALK to load the file. At the next prompt, press [RETURN] to return to the main menu. Enter TELECOM and set it for 9600 baud as above. Then enter TERM and press [F5] for downloading.

Type in a file name at the prompt. At this point, the word "Down" appears (over [F5] in inverse notation. Next, on the Atari, press [S] for Spool Text from the main menu. When the prompt 'D1:' appears, backspace to the 'D' and type R1: [RETURN]. Transfer will now take place.

If you use some other terminal program, make sure that translation is set to light. The normal Upload procedure (not the one described above, but the one described by the terminal program's documentation) should work for programs other than TELETALK. If you have any problems with data transfer, try using a lower transfer rate, such as 4800 or 2400. Even 1200 is tolerable. Also make sure that both the Atari terminal program and TELCOM are set at the same transfer(baud) rate.


The cable and procedures outlined in this article give you the opportunity to move into the world of notebook computers without leaving your Atari behind. We've covered the three major book-sized computers that are currently available. The next step is yours. Your Atari can be an integral part of your move into the realm of easily transportable computers. It can interface with all of the major products on the market today, and can provide benefits and features that no notebook computer can match. If you have an Atari, and a friend has an Epson, a NEC, or a Model 100 notebook computer you can transfer files between the two computers and easily share your computer experiences. And this technique (with some modifications) can work with other kinds of computers as well. The opportunities are definitely out there; look into them -- and let us know what you discover.

Table 1
Pin Assignments for RS-232C/850SP1 Connection
Pin      Description              Goes to 850 Pin
 2       TxD--Transmit Data       4 Data in
 3       RxD--Recieve Data        3 Send Data
 4       RTS- Request to Send     7 RTS Out
 5       CTS--Transm. Auth.       8 CTS In
 6       DSR--Data Set Ready      1 DTR Out
 7       GND--Signal Ground       5 Sig. GND
 8       DCD--Data Carr, Detect   2 Carr. Det. (CRX, In)
 20      DTR--Data Carr, Ready    6 DSR In
Robert Siegle is an associate Professor of English at Virginia Tech. He uses his Atari 800 and an Epson HX-20 notebook computer to handle a number of research, writing and management projects. Bob Kahn works for Dorothy Derringer in the Learning Systems Group at Atari, Inc.