tells the computer that the printer is active and ready to receive data.
a blue cube), and zero or near zero voltage to represent a 0 (shown here as a red sphere).
3 - After the voltages have been set for all data lines, line 1 sends a strobe pulse for a
microsecond to the printer, stating that she can read the data line voltages.
4 - A sign of the printer on line 11 tells the PC where the printer is busy managing the byte just
being sent, and that the PC should wait to send the next byte until the signal is disabled. A signal
Busy can be generated if the printer is printing the last character, storing the byte in a buffer, or if the
buffer is full, or there is any problem with tape or some other factor that prevents the printer manage other
data.
5 - A printer signal on line 10 acknowledges receipt of data sent in lines 2-9 and informs the PC that
printer is ready to receive another character.
6 - A signal line 12 tells the printer to the PC that the printer is out of paper.
7 - Line 15 is used by the printer to inform the PC other error conditions like open door or failed
print head, but does not specify the type of error occurred.
8 - A PC signal on line 16 causes the printer to restart itself as if it were turned off and on again.
9 - A low-voltage signal or no PC at line 14 tells the printer to advance the paper one line when
receive the return code of the car (carriage return). A high voltage signal tells the printer to advance the
paper in a line only when it receives a line feed code (line feed).
10 - A signal line 17 PC tells the printer not to accept the data. This line is used only in some
printers, designed to be activated and deactivated by the PC.
Note - The lines 18 and 25 are simply land lines.
Source: Evolution of Computers
No comments:
Post a Comment