Measurement Computing Personal488 rev.3.0 For DOS & Windows 3.Xi - Manual (Page 198)

II. SOFTWARE GUIDES - 9. Driver488/SUB 9J. Utility Programs
Personal488 User’s Manual, Rev. 3.0 II-183
9J. Utility Programs
Topics
•
Printer & Serial Redirection ..................................................... II-182
•
Removal & Reinstallation........................................................... II-184
MARKDRVR & REMDRVR..........................................................................II-184
•
Moving Files from an IEEE 488 (HP-IB) Controller to a PCII-185
PRNTEMUL Files .........................................................................................II-185
Configuration of the IEEE Interface for PRNTEMUL............................II-185
Running PRNTEMUL ..................................................................................II-185
Data Transfer ...............................................................................................II-186
Printer & Serial Redirection
IEEELPT and IEEECOM are stand-alone utilities (Driver488 need not be installed to use them) that
allow programs which are unaware of the IEEE 488 bus to control IEEE 488 bus devices as if they
were printer (
IEEELPT ) or serial ( IEEECOM ) devices. They automatically redirect communications
destined for printer or serial ports to specified IEEE 488 bus devices. For example, the command:
C> IEEELPT IEEE05
will configure IEEE 488 bus device 5 to appear as the first parallel printer port ( LPT1: ). Any text that
is destined for LPT1: will, instead be send to bus device 5 . For example, the COPY command:
C> COPY TEXTFILE.DOC LPT1:
will copy the contents of TEXTFILE.DOC to the IEEE 488 bus. Any software which prints to LPT1:
will now send its data to IEEE 488 bus device 5 .
Similarly, the command:
C> IEEECOM IEEE12
will redirect communications to and from the COM1: serial port to IEEE 488 bus device 12 . Thus, a
plotting program which expects a serial plotter can communicate with an IEEE 488 plotter using
Power488.
Serial port redirection is often less effective than printer port redirection because many programs
control the serial port hardware directly and bypass the redirection program. It is still possible to
redirect output from such a program to an IEEE device if that program can be configured to send its
output to a disk file rather than directly to the printer or plotter. If a file such as
\DEV\COM1 is
specified, the program will act as though the data were being written to an actual disk file, while the
output will be sent to the IEEE 488 bus device to which
COM1 was redirected. The program may even
issue a warning message that the specified file exists and will be overwritten. If it does, then the user
may tell it that it may delete or overwrite the file. No harm can result from trying to delete a device.
To understand how these programs are used, it is necessary to keep in mind the difference between
logical and physical devices. When the computer first boots up, it takes an inventory of the installed
hardware. It might, for example, find two parallel printer ports, and one serial communications port.
These are the physical devices. The physical device,
LPT1 (note the absence of the colon) is the printer
port first identified by the computer. The logical device LPT1: (with the colon) refers to the device
which is currently configured to receive data to be printed. The computer maintains two tables of four
entries each to keep track of physical devices by logical device name. In the case of two printer and
one serial port, these tables initially appear as: