Owner`s manual

Page A-2 Appendix A
The Eagle 550’s I/O interface board, the AM-319-20, includes four on-board RS-232
serial ports. All four serial ports have standard RJ-45 connectors and use the
AM318.IDV interface driver for octal port numbers 0 through 3.
The Eagle 550 system chassis has seven rear panel slots designed for serial I/O
expansion. These slots can be used for standard Alpha Micro I/O paddle cards, such as
the AM-359, which connect to the A-channel expansion bus on the AM-319-20 board.
For even more flexibility, the first six slots can be used to house I/O paddle cards, and
the seventh slot can be used for connection to an AM-3501 I/O expansion chassis. The
expansion chassis can accomodate an additional seven serial I/O paddle cards which
are connected back to the B-channel expansion bus on the main AM-319-20 board.
AM-359 serial I/O expansion paddle cards connected to the A-channel bus use the
standard AM359.IDV interface driver. AM-355 serial I/O expansion paddle cards
connected to the A-channel bus use the new AM355A.IDV interface driver. Paddle
cards connected to the B-channel bus use the AM355B.IDV and/or AM359B.IDV
interface drivers.
Although several different types of I/O paddle cards are available, Alpha Micro highly
recommends the use of AM-359 eight-port serial I/O cards for serial I/O expansion. The
AM-359 paddle cards use the same standard RJ-45 connectors and cables as the Eagle
550’s on-board ports, they can be purchased with or without optical isolation protection,
and they consume less I/O select addressing than any other I/O expansion card, which
allows for more ports per I/O channel!
WHAT IS RS-232?
All Eagle serial ports support RS-232. RS-232 is the name of a standard developed by
the Electronic Industry Association (EIA) to encourage standardized interfacing of
devices to computer systems. The letters RS stand for Recommended Standard. The
RS-232 interface standard specifies electrical signal characteristics and names, and
defines the functions of the signal and control lines that make up the interface.
Basically, implementing this standard involves assigning standardized signal definitions
for the various pins of the RS-232 connector at either end of your terminal or printer
cables. For example, the wire attached to Pin #2 carries the signal interpreted on the
computer end as "Input Data from Terminal" and on the terminal end as "Transmit Data
To Computer."
You enable these specific signals by attaching cable wires to certain connector pins.
If a terminal or printer manufacturer says their device is RS-232 or RS-232C compatible,
it will probably be easy for you to connect it to your Alpha Micro computer system.
Before constructing the cable to connect a printer or terminal to your Alpha Micro
computer system, you need to consult the manufacturer’s manual accompanying the
device. It will tell you how to wire the connector on the device end. Few devices use all
of the defined signals, in most cases, you need to connect only three or four pins.
Eagle Series Computer Owner’s Manual, Rev. 03