RS232 Communications – up to 50 feet
RS232 devices can be plugged straight into a computer?s serial port (also known as the COM port). The serial port on a PC is a full-duplex device, meaning that it can send and receive data at the same time. The RS232 serial interface is very useful for point-to-point communication. For example, port COM1 in a PC can be used for a mouse, port COM2 for a modem, etc. These are examples of point-to-point communication: one port, one device. This method of communication requires software installation on a designated PC which will control the messages sent to the sign.
A 50 foot cable length limit is recommended to avoid electro magnetic interference (EMI) resistance of the cable. Splicing cable or linking cable to extend connection beyond 50 feet may result in communication problems or failures.
Note: Newer model laptops may not have a serial port which would require the use of a USB to Serial Port converter.
RS485 Communications – Up to 4,000 feet
RS485 is used for multipoint communications, allowing more devices to be connected to a single parent cable. The RS232 to RS485 Interface Converter allows information exchange in full duplex mode over two twisted pairs. In short, it converts RS485 signals to RS232 signals.
Belden 9830 twisted pair cable, or CAT5 cable are used to connect the RS485 converter box to the display. In both cases indoor cable cannot withstand the exposure to outdoor conditions. so the correct grade of cable must be installed.
Data cable should NEVER been run through a conduit with power cable, or run in any close proximity to motors, transformers, ballasts, or any other sources of electro magnetic interference (EMI). Data cable should be placed at a minimum distance of 6 inches from any power/electrical conduit.
Maximum distance for between the converter box and the LED sign is 4000 feet.
Wireless Transceiver Communications
A transceiver is a combination transmitter/receiver in a single package. Radio Frequency (RF) communication works by creating electromagnetic waves at a source and being able to pick up those electromagnetic waves at a particular destination.
Line-of-site when speaking of RF means more than just being able to see the receiving antenna from the transmitting antenna. In order to have true line-of-site no objects (including trees, houses or the ground) can be in the area around the visual line-of-sight that radio waves spread out into after they leave the antenna. This area must be clear or else signal strength weakens.
Communication from the computer to the transceiver is limited to less than 50 feet (standard RSR232 communication). Depending on the transceiver selection, wireless communication ranges from 800 feet to a maximum distance of 5 miles.
Ethernet Communications Overview
Ethernet is an inexpensive LAN (Local Area Network) technology used for transporting information from one location to another. Addressing on an Ethernet LAN is very similar to addressing on a PC, each recipient is accessible by its own unique IP address. Each Ethernet segment can only be so long before the signals begin to fade or get corrupted due to line noise.
Direct CAT5 Connection
Many LED signs feature an optional onboard Ethernet controller, making wired Ethernet communications a simple process of connecting cable between a network and the display itself. Communicating by wired Ethernet requires a CAT5 cable with RJ45 connectors.
Wireless Ethernet Communications (WiFi)
A Wireless LAN is usually an extension to a wired LAN. WLANs provide most of the functionality of wired LANs, but without the physical constraints or costs of physically installing the wire. Packets of data are converted into radio waves that are sent to other wireless devices or to a wireless access point (WAP) – a device that bridges wireless traffic to a wired network.
Fiber Optic Ethernet to Serial Converter
Fiber optic cable offers two main advantages over twisted pair cable. First, data may be carried much further over fiber. Second, fiber is immune to electromagnetic interference. Ethernet carried over multimode fiber is known as 10BASE-FL. Optical fiber has several advantages over copper media. Reliability and performance are enhanced with optical fiber media because fiber does not absorb electrical signals. In addition, fiber allows 2 km, or 6561.68 feet, between stations using multimode fiber.