Daktronics Galaxy AF-3150 Series, Manual

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Introduction
1-3
1.2 Network Concepts
The concept of using LED displays as a cost effective, high impact method of
communication is rapidly growing throughout many industries and businesses. The
reasons for this growth are many, but the need for additional features and the
complexity of multiple display installations has emerged. Daktronics display systems
have been designed to meet those needs.
The common thread to most client requests is a means of programming and
controlling a group of displays from a central control point. Daktronics responded by
developing a powerful system of interconnecting and controlling displays. Great care
has been taken to design products that will satisfy a wide variety of installations.
Some of the design goals of these systems include the following:
•
Easy transfer of messages
•
The ability to tell a display or group of displays in the network which
message should run
•
The ability to determine the status of any display on the network
•
The ability to control multiple display technologies on the same network
There are five (5) network systems available: RS232, RS422, modem, fiber, and
radio. Up to 240 displays can exist on one network.
RS232 Network
RS232 (EIA/TIA-232-E) is a standard communication interface that employs a
single-ended serial transmission scheme that uses a maximum cable length of 7.6
meters (approximately 25 feet). This interface was designed for computer
communication at short distances. The computer used will require an RS232
communications port. Refer to
Section 3 for additional information.
RS422 Network
RS422 (EIA/TIA-422-B) is a standard communication interface that utilizes a
differential balanced transmission scheme that uses a typical maximum cable length
of 1.2 km (approximately 4,000 feet). The main advantage to RS422 over RS232 is
the longer cable length that is possible. A signal converter is needed to convert the
computer’s RS232 to RS422. Refer to
Section 3 for additional information.
Modem Network
The modem is a standard communication interface that utilizes standard phone
transmission lines. The phone company assigns each phone line a number that the
modem at the computer uses to communicate to the modem in the display. Each
modem display network needs to have a dedicated phone line assigned to it. Refer to
Section 3 for additional information.