HP 98568A Installation Instruction page 154

HP 98628A Datacomm Interface
SKIP?
If this is the first (or only) Datacomm Interface you are
installing, you can skip to step 3. The select code is preset to
20 and need not be changed.
a. Find the set of select code and interrupt level switches by referring to
Figure 5-24. Switches 0 thru 4 in this group determine the select code.
b. Set these switches to one of the five select codes given below, unless
you have used them elsewhere (check the Select Code Record on the
Chapter 5, "Interface Cards" tab to see which ones you have used).
Refer to the installation note that came with the interface if you need
additional switch settings.
Select Code 10 Select Code 15
Select Code 17
Select Code 1 9
Figure 5-25.
5-58 Adding Interface Cards