Controlled Decision: RS-232 vs.IP
Look at the back of any major-brand AV control processor these days and you'll probably see a snapshot of an industry in transition.
Look at the back of any major-brand AV control processor these days and you'll probably see a snapshot of an industry in transition. On one side of the device lies the gateway through which the industry appears headed: the TCP/IP network port. Nearby is the route control commands have largely taken to date: the RS-232 serial port.
Dan Walter of AV integrator ExhibitOne says he prefers the reliability of RS-232. "There's one less thing to check."
Credit: Wes Johnson / WPN
From projectors to audio DSPs to videoconferencing codecs–even film screens–pro AV manufacturers are increasingly building devices that can be controlled via an IP network where serial control has worked well in the past, thank you very much.
"When I first started at AMX almost eight years ago, every piece of equipment was either IR- or serial-controlled," says AMX chief technology officer Robert Noble. "Now IP-based devices are 20 to 25 percent of what we're seeing. And in three years, that will be up to 50 percent."
With the proliferation of devices with Ethernet ports, many AV systems integrators have become early adopters, enamored by the advantages of network-based control–faster data transfer speeds, broader reach, etc. And many of them have become comfortable with the myriad complexities involved in network engineering.
"Once you're on the network and you're packetized, there are pretty much no limits to what you can control and where," says Blaine Brown, director of technology for Indianapolis-based AV integrator Sensory Technologies.
"From my office, I can reach out and touch an IP-connected device in another building," Noble adds. "You couldn't do that with RS-232."
Brown and his team are so comfortable with IP-based control systems that they'll often build a dedicated network if a client doesn't already have one to support the AV system they're putting in. "We hope this trend toward TCP/IP control continues," he says. "We can control as many devices as we want as long as the processor has an Ethernet port, and in a lot of cases we're able to utilize network infrastructure that's already in the building."