Specifications

7
Chapter 1 - Introduction and Description
Product Description
The ISI4608 is a multiport serial port expansion card which adds data
buffering on each port for enhanced serial port performance. The
ISI4608 features an on-board microprocessor to coordinate the
communications activity of your local and remote terminals. Using an
ISI4608 to provide additional serial connections enables your
system's processor to perform more efficiently. This is because the
ISI4608 handles all of the byte-by-byte interrupts generated by
asynchronous terminals and stores the data in buffers. The
processor works together with 256K bytes of RAM to allocate
resources dynamically to the most active port. The ISI then generates
one interrupt for an entire block of information and transfers the block
to the system's microprocessor.
The ISI4608 has one 78-pin (DB78S) connector which interfaces with
an eight-port fan-out, or “ octopus ”, cable (supplied with the card),
providing eight additional serial ports. It is a "3/4 size" add-on card
which supports a high-speed interface up to 115.2K bps. The
ISI4608 features one bank of 8 DIP-Switches for I/O address
selection and one jumper block for IRQ selection.
ISI4608 Applications
The most common application for the ISI4608 is where a powerful
microcomputer is being used as a server or host, but lacks enough
connectivity to accommodate the desired number of users. For this
application, the ISI4608 is the ideal solution. The ISI4608 provides
eight additional serial ports with every card installed, with potentially
four additional cards installed per system -- for a total of thirty-two
serial ports per system.