DOCUMENTATION FOR "NETERM.BIN" The program, "NETERM.BIN", uploaded at about the same time, is a bare bones program that illustrates the technique of printing while on-line, without sending hold-offs to the host (e.g., CONTROL S). Written in BASIC for a C-64, it was tested with a C-64C, an OKIMATE 20 serial printer, and a 1670 modem. Unfortunately, I could get reliable operation only at 300 baud. But I think that the method employed is usable at higher baud rates with other printers. The OKIMATE 20 is highly intolerant of delays in character transmission caused by -NMI interrupts. The CBM serial port specifiction is 200 microseconds from -DATA line going high to start of -CLK pulses for a valid character. But my measurements indicate that with considerably shorter delays, the printer will unlisten itself. The program, when LOADed and RUN, transfers 918 bytes of ML to the region from $C000 to $C395. The BASIC program occupies $0801 to $0F7C. Any linenumber between 20 and 2020 may be deleted, edited, or added. Before reSAVing, be sure to change the end of line 10 from GOTO2020 to GOTO0020. The program was designed for ease of modification. It is not offered as a finished product. But rather as a demonstration of a technique that may be in little current use. The variables, F2$, F4$, and F6$, should be changed to your local CIS 'phone number, your user ID, and your password, respectively. The printer device number, secondary address, and control characters, may be changed as required. After getting past the printer prompt(s), press F1 to enter terminal mode. You exit terminal mode with F3. After dialing the 'phone number (F2), and sending a CONTROL C by pressing the STOP key when connection is made, press F4 to respond to user ID prompt, and F6 to answer password prompt. If an ASCII text file is to be REAd, after typing in the FILENAME, do not press RETURN. Press F5 instead. The header should dissapear to indicate "printer on" mode. What is displayed on the screen is what is being received from the host in real time. The interruptions occuring during printhead activity are compensated for by rapid receiver buffer printout when the printer holdoff is removed. You're never more than a line or two behind. A "receive only" RS-232 routine is used and the receiver buffer is dumped into a 35 K capture buffer. The printer is fed from the capture buffer. When the "Press <CR>" prompt appears at the end of the file, press F7, (the only key operable in "printer on" mode). The header should reappear, indicating "printer off" mode. With my OKIMATE 20, in draft mode, I would by now have printed out most of the buffer. In NLQ mode, however, I would be far behind. I suspect that other "Commodore compatible" printers may be significantly faster. But you have a hard copy of most, if not all, of what you received. After exiting terminal mode, by pressing F3, the rest of the buffer may be printed out. ASCII/PETASCII and PETASCII/ASCII conversion is used. When pressing F7 while on-line, to stop printing, keep the key down until the header appears. The keyboard is not read during printhead movement. All comments, suggestions, and criticisms are welcome. John Iannetta 73510,2152
Amiga7878