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Appendix A
AM-6060 Computer Owner's Manual, Rev. 00
SERIAL I/O CONNECTORS
The AM-6060's I/O interface board, the AM-301-10, includes four on-board RS-232 serial ports,
numbered 0 - 3. All four serial ports have standard RJ-45 connectors and use the AM318.IDV interface
driver.
The following sections discuss the RS-232 standard, considerations if you want to build your own cables,
and cable kits available from Alpha Micro for connecting the serial ports to various types of device.
What Is RS-232?
All AM-6060 serial ports support RS-232. RS-232 is a standard developed by the Electronic Industry
Association (EIA) to encourage standardized interfacing of devices to computer systems (RS stands for
Recommended Standard). RS-232 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. Although printer cables are sometimes a little more complicated on the
printer end, terminal cables are often the same on both computer and terminal ends.
Alpha Micro uses RJ-45 connectors for RS-232 device connection. The standard maximum length of RS-
232 cables is 50 feet between devices. If you use low-capacity twisted-pair cable you can extend the
length up to 100 feet.
Important Note
The Federal Communications Commission (FCC) has established rules regarding allowable emission
levels of Class A computing devices (ref: Subpart J of Part 15 of FCC Rules). The Alpha Micro systems
to which this manual applies have been determined to be in compliance with the FCC rules. However,
you should be aware that if other devices, such as terminals and printers, are attached to these systems,
even if the devices are attached in accordance with the instructions contained in this manual, the
resulting configuration may not be in compliance with the referenced FCC rules. Corrective measures, if
any are required, are the responsibility of the user. Information on emission levels of peripheral devices
should be obtained from the manufacturer of the device.
