DOCUMENTATION FOR PC2PRN.LDR Program PC2PRN.LDR provides a means for sharing a printer between a personal computer and the Model 100 laptop computer. This is a machine- language program, and I have no way of testing whether it works with the Tandy 102 or 200. First, I will describe the way it is used. The hardware requirements are: a personal computer with a serial communications port, a cable connecting it to the serial communications port of the Model 100, the Model 100 (of course), and a printer connected to the parallel port of the Model 100. Any connection between the Model 100 and the parallel printer that works for printing with the Model 100 should work for printing with the PC and this program. Serial cable connections (assuming a serial port with a 25-pin connector on the PC): Model 100 PC --------- -- GND 1........1 GND TX 2........3 RX RX 3........2 TX RTS 4........5 CTS CTS 5........4 RTS DSR 6.......20 DTR GND 7........7 GND DTR 20........6 DTR Note that this was the standard cable sold by the Portable Computer Support Group for use with Disk+ when I bought it in 1985 (the rest of the pins are connected straight through, but are not internally connected in the Model 100, so they don't matter). Here's a picture, for clarification: +------+ +-------+ +-----+ | PC |.....| Model |.....| LPT | | | | 100 | | | +------+ ser +-------+ par +-----+ Back to operation of the program: When this program is running, the Model 100 acts as a serial-to-parallel converter for the data being sent out by the PC. Any (yes, any) characters sent out the serial port of the PC are sent to the parallel printer attached to the Model 100. There is no translation of tabs, nulls, controlZ's, or any special characters, so that even graphics may be sent through this program. To print directly from the Model 100, simply terminate the program (using F8) and print as you normally would from the Model 100. There is one small catch: printers connected to PC's normally do not generate a linefeed when a carriage return is sent, whereas the Model 100 expects a printer attached to it to generate this linefeed. I deal with this by setting up the printer in the normal fashion for use with a PC, and then I use a program on the Model 100 that accompanies all CR's (carriage returns) sent to the printer with a linefeed (such as LPTLF). DETAILED INSTRUCTIONS: Download the program PC2PRN.LDR to your Model 100, naming it PC2PRN.DO. Enter BASIC, and type CLEAR 256,MAXRAM-1000 LOAD "PC2PRN.DO" SAVE "PC2PRN" KILL "PC2PRN.DO" RUN The program presents you for a range of end addresses that are possible, given your current values of HIMEM and MAXRAM. You may enter the address that you like, or you may just press and it will create it at the highest address you have available. When the program is done, you will have a new program, PC2PRN.CO, in your list of files, as well as PC2PRN.BA. At this point, you may wish to store PC2PRN.BA to cassette tape or disk; you won't need it again unless you decide you want to change the loading address of PC2PRN.CO or PC2PRN.CO gets wiped out of your memory. To run PC2PRN.CO, simply move the widebar cursor over it and press return. The screen clears, except for the row of function key labels at the bottom. They are: F1: RTS, F2: DTR, F3: LPT, F4: LCD, F5: DSR, F6: CTS, and F8: MENU. Any that are currently "ON" are in inverse video. Now, you need to set up your PC. Type in the commands MODE COM1:9600,n,8,1,P MODE LPT1=COM1 assuming that the serial port on your PC that is connected to your Model 100 is COM1. Make sure your printer is on. Now, print a short file from the PC, for test purposes. You should see the characters going across the screen, and they should also appear on your printer. Notice that the characters on the LCD of the Model 100 do not scroll, but output returns to the top line after the bottom line is filled. Also notice that control characters are made visible by a caret (^) in front of the control key that would generate them. (You should see frequent ^M^J combinations, indicating the carriage return/linefeed pairs.) You should also see the labels for RTS and DTR going on and off. This indicates the hardware handshaking going on between your Model 100 and PC. For higher printing speeds, you may turn off the output to the Model 100 screen by pressing F4, indicating LCD. Pressing the active function keys F1 through F4 toggle their respective functions ON and OFF. Likewise, press F4 again to turn on screen display and press F3 to turn off transmission to the printer. Now, you have a way of displaying the characters coming out of the serial port of your PC. One other thing to note: characters typed at the keyboard of the Model 100 are sent to the PC. One way to have some fun with this is to turn everything on (press F3 again to turn on LPT transmission). Now, type CTTY COM1: at the keyboard of your PC. Note that the PC does not give another prompt on the screen; instead, there it is on your Model 100! Type a command at the keyboard of your Model 100; what you type is printed in inverse video, and the PC echoes each character. When you press ENTER, the PC should execute your command. The information from the PC should also be appearing on your printer. Keep this in mind in case your PC monitor dies (mine has, twice). To terminate this insanity, type CTTY CON at the keyboard of the Model 100; a new prompt should appear on the screen of your PC. Before turning anything off, terminate the program by pressing F8 (MENU). Occasionally, it does seem to get "hung up" if something is turned off while the program is running. Pressing SHIFT-BREAK usually will get you out, but it is better to remember to terminate the program first. Bill Boyd 75715,70