HP 8920A Programmer's Manual page 390

Chapter 7, IBASIC Controller
Method #1. Program Development on an External BASIC Language Computer
NOTE:
390
There are two ways of allowing easy conversion of all HP-IB commands to a different
address. The first way is to establish a variable to which the 3-digit address number is
assigned.
For example
10 Addr = 714 ! Sets the value of variable Addr to be 714.
20 OUTPUT Addr;"*RST"!Commands the Test Set to reset at address 714.
To change the address, simply change the value of variable Addr to 814.
For example
10 Addr = 814 ! Sets the value of variable Addr to be 814.
20 OUTPUT Addr;"*RST"! Commands the Test Set to reset at address 814.
A second method is to assign an I/O path to the desired I/O port.
For example
To control device #14 on the port with select code 7.
20 ! Establishes IO path to select code 7 address 14
10 ASSIGN @Device TO 714
30 ! Commands Test Set to reset at address 714.
20 OUTPUT @Device;"*RST"
To change the address, simply change line 10 to
10 ASSIGN @Device TO 800.
The dedicated HP-IB interface at select code 8 conforms to the IEEE 488.2 Standard in all
respects but one. The difference being that each instrument on the bus does not have a
unique address. The Instrument Control Hardware determines which instrument is being
addressed with the command syntax. As such an explicit device address does not have to
be specified. The address 800 and 814 are equally correct.