422
Sensoray's model 422 is a bus-to-bus adapter that extends an ISA bus onto a card rack of STDbus I/O boards, thereby enabling the PC to directly interact with STDbus boards. It has three parts: an ISA board (Model 402), an STDbus board (Model 7402) and a set of two flat cables (26 and 34 conductors) that connect the two boards. The ISA board includes a 2-pin terminal block that may optionally be connected across the PC's reset pushbutton to enable an STDbus watchdog timer to reset the PC.
Device driver
Sensoray doesn't offer a device driver for Model 422 because it was developed during the reign of Windows 98 (which didn't require a device driver). Later versions of Windows (as well as Linux and other modern operating systems) typically do require device drivers, so if you plan to use model 422 with a newer operating system then you must create your own device driver.
The development of such a driver is beyond the scope of this appnote, but the driver itself has very simple requirements. The ISA board decodes the high byte of the 16-bit ISA I/O address bus, while the low address byte is directly passed through to the STDbus. All STDbus I/O boards are mapped into a 256-address window in the ISA I/O space [0x0100:0x01FF]. For example, reads/writes to ISA I/O address 0x0123 will access the STDbus 8-bit I/O address 0x23. Consequently, the device driver can simply map the physical address range [0x0100:0x01FF] into user space; nothing more is required.