51 | 8 4
{ union REGS r;
r.x.dx = port; /* serial port */
r.h.ah = 0; /* int14 function0:initial serial port */
r.h.al = code; /* initialization code */
int86( 0x14,&r,&r );
}
5.1.2 GPIB Interface Instruction
5.1.2.1 GPIB BUS
The IEEE488 (GPIB) universal parallel bus interface is an internationally accepted intelligent
instrument bus interface standard. IEEE is the English abbreviation of Institute of Electrical and
Electronics Engineers, 488 is the standard number.
Through this interface, it can communicate with
a computer or other intelligent device, and can easily form an automatic test system together with
other test instruments. Multiple test instruments can be connected simultaneously on the same bus.
For this tester, it adopts the IEEE488.2 standard, and the interface board is an option.
The control
command system is open, and the user can use the computer operation interface provided by the
tester, or can program the system according to the control command to achieve the purpose. The
control command system supports most of the functions of the tester, that is to say, almost all
functions of the tester can be operated on a controlled computer to realize the remote control of the
tester.
When using tester’s GPIB system, the following points should be noted:
The total cable length of a bus system should not exceed 2 meters and the product of the total
number of connected test equipment, and the total length of the cable is no more than 20
meters.
Maximum 15 test equipment can be connected on the same bus at the same time.
There is no restriction on how the cables are connected together, but it is recommended to
stack only 4 back connectors on any test equipment.
