I-O Display Systems Basic I/O Product - Manual (Page 13)

The Basic I/O 1
1-8(Vol.1)
COMMUNICATION PROTOCOL:
The BASIC I/O Communication Protocol is 100% compatible with the Opto-22 Optomux™
protocol. This ASCII printable serial protocol uses a “speak-only-when-spoken-to” format
where only the host can initiate an information exchange. Each BASIC I/O unit installed in a
network has a unique address. This address is embedded in the instruction generated by the
host computer. Every BASIC I/O chassis receives the instruction but only the unit which is
set to the address found in that instruction will respond. Every string of data whose length is
greater than one character is followed by a checksum to ensure data integrity. This protocol
also provides an instruction verification mode for further data transmission reliability.
As a result of the specific nature of the BASIC I/O communications protocol, the RS-422 or
RS-485 network can be shared with other devices whose protocol is similar.
A knowledge of serial communications, hexadecimal to decimal conversion, and string data
manipulation is required to compose custom user generated Host software. DuTec’s EASY
I/O software is designed to minimize these obstacles.