The ADAM-4500 has a DB-9 pin connector as its RS-232 port connector. Since the connection
for an RS-232 interface is not standardized, different devices implement the RS-232 connection
in different ways. If you are having problems with a serial device, be sure to check the pin
assignments for the connector. The following table shows the pin assignments for the ADAM-
4500's RS-232 port.
Pin No. Description
1 DCD
2 RxD
3 TxD
4 DTR
5 GND
6 DSR
7 RTS
8 CTS
9 RI
Table 2-1: Pin Assignments of RS-232 Port
RS-485 Connection
The RS-485 standard supports half-duplex communication. This means that just two wires are
needed to both transmit and receive data. Handshaking signals (such as RTS, Request To Send)
are normally used to control the direction of the data flow. A special I/O circuit in the ADAM-4500
automatically senses the direction of the data flow and switches the transmission direction. No
handshaking signals are necessary. This RS-485 control is completely transparent to the user.
We recommend that shielded twisted-pair cables complying with the EIA RS-485 standard be
used in the network to reduce interference. Only one set of twisted-pair cables is required to
transmit both Data and RTS signals. We advise use of the following standard colors for the
communication cables.
DATA + Yellow
DATA - Green
This chapter explains how to program applications and download programs into the ADAM-4500
controller. Additionally, it points out limitations and concerns of which you should be aware.
3.1 Programming
The operating system of ADAM-4500 is ROM-DOS, an MS-DOS equivalent system. It allows
users to run application programs written in assembly language as well as high level languages
such as C or C++. However, there are limitations when running application programs in the
ADAM-4500. In order to build successful applications, you should keep the following limitations
and concerns in mind.
Mini BIOS Functions
The ADAM-4500 provides only two serial communication ports for connecting peripherals, so the