Zenith Z-100 Series, Reference Manual, Page: 135 / 163

Page 8.2
Serial and Parallel Input/Output
Configuration
Configuration hardware jumpers are provided on the floppy disk controller card
for the serial I/O ports and on the standard memory card for the parallel interface.
Serial Port Configuration
Serial port ¹I (C OMI), physically the top connector on the rear of the floppy
disk controller card, is configured to interrupt request ¹4 (IR4). The lower connec-
tor, COM2, comes configured as Interrupt request ¹3 (IR3) by section 2 of jumper
block J502. You may configure this port to any other interrupt number desired
in the range from 2 to 7, by moving the jumper at section 2 to one of the other
sections of J502 corresponding to the desired interrupt number. You must bear
in mind, however, that certain of these interrupts are already in use by other
devices and confusion may result when using more than one of these devices
at the same time. For instance, IR7 is the interrupt assigned to the parallel device
port but may also be selected for COM2 if the jumper is placed at section 6
of J502.
NOTE: The disk controller I/O card may have only one RS-232 serial port. If
this is the case, all references to COM2 may be ignored.
Parallel Port Configuration
Two hardware jumpers on the standard memory card, the one with the DB-25
connector installed, allow you to select the port address of the parallel interface.
It is suggested that you normafly use the configuration for port address 378H
for a parallel printer, since the 3BCH address corresponds to the IBM PC mono-
chrome port. Bear in mind also that two combinations of the configuration jumpers,
J402 and J403, will disable the parallel interface. Table 8.1 shows the possible
selections obtainable using these jumpers.
Table 8.1. Parallel Port Address Selection
J403 J402
PORT ADDRESS
0
0 3BC
0
I 378
I 0 Disable port
I I Disable port