What is a Networked Projector?

From the outside, networked projectors don’t look muchdifferent from other models. The difference is in the projector’soperating system and menu structure. Through the use of serial(RS-232C) or TCP/IP protocols, a networked projector can be controlledfrom remote locations, provide instant status updates, and evendownload presentation software files for later viewing.

Sharp’s full line of installation LCD projectors support oneor both of these protocols. The first (RS-232C) has been astaple of the systems integration industry for years, and is alow-speed (9600 baud) serial interface for direct control of projectorfunctions. It can also be used to move large files and will even talkto other projectors in a multi-screen installation.

Sharp's XG-P25/P20XU

The second interface is better known in the information technology(IT) world. Transmission Control Protocol/Internet Protocol isthe basis for Internet communications and the interface between devicesin a local area network (LAN) or those in multiple networks. Thelimiting data rate of a TCP/IP interface is dependent on the network towhich it connects, and those data rates can easily exceed 100 megabitsper second (Mb/s).

To be considered “networked,” a projector must supportat least an RS-232C interface. While not as fast as TCP/IP networks,the RS-232C handshake is sufficient to send and receive commands fromprojectors and obtain updates on the projector’s operatingstatus. Multiple projectors can be daisy-chained and assigned uniqueRS-232C addresses so they respond only to those commands sent tothem.

TCP/IP networking works much the same way, except at a higher speed.Each projector is assigned a unique IP address, just as a desktopcomputer, notebook, laser printer, digital camera, or server might be.As thousands of data packets flow through the network, each projector“grabs” only the packets addressed to it.

These packets might contain commands, status inquiries, or stillimages. By using standard interfaces such as Simple Mail TransferProtocol (SMTP), each projector functions as both a server and aclient, depending on which commands and functions are needed.

Wiring up either network isn’t a major headache. RS-232Ccontrol can use standard twisted-pair plenum wire, or Cat 5/6multi-wire cable. IP-connected projectors use Cat 5/6 cableexclusively, and this type of cable is inexpensive and easy to installwith crimp connectors. Best of all, it is the standard for otherIP-connected devices within a network, so, tying into existing companyor institutional LANs is a much easier job.