Unlike many universities, the Texas A&M Health Science Center (HSC) is actually a consortium of colleges that stretches over 400 miles of eastern Texas. In order to offer its students a comprehensive curriculum, the schools of the HSC – Pharmacy, Dentistry, Nursing, Medicine and even graduate biomedical research – have come to rely heavily on distance learning. So much so that Senior Network Engineer Sean Alexander calls it “mission critical.”

“It’s not ‘Let’s just hope it works,’” says Alexander. “We cannot have classes at all without video conferencing. That includes fully functional audio with student participation.” With even more distance learning classes planned for the spring semester, the Health Science Center asked CCS Presentation systems of Houston to equip five large lecture halls with the newest distance learning technology available, two in Temple, Texas, and three in Kingsville.

“They wanted a stable technology platform that would allow them to seamlessly call another campus,” says Ben Pickrel, Sales Manager for CCS. “But we also added another important feature. When a student asks a question they want that student’s face on the screen so the professor can see it. So we installed a push to talk mike at every other seat. When the student pushes the mike button the camera snaps to that location. It’s not a close up. It might be 4 to 8 people all in the same shot, but at least you see the person asking the question.”

Making Push to Talk Possible
While the concept may sound simple, the technology that makes it possible is not. Up until now, push-to-talk microphones have never worked well with the acoustic echo cancellation so vital to distance learning applications. “Echo cancellation isn’t a luxury in audio conferencing, it’s mandatory,” says Scott Woolley, Director of Product Marketing, Professional Audio for ClearOne, a leader in the field of audio conferencing. “Without it, the echo is not just a nuisance, it’s completely disruptive to the application.”

What the acoustic echo cancellation does is prevent a person’s voice from looping back to him through the audio system. In distance learning, when a professor speaks into the microphone in his classroom, his voice comes out of the loudspeakers at the distant site. Without echo cancellation, the professor’s voice would be picked up by microphones there and sent back to him after a brief time delay, causing an echo.

“In order for the echo canceller to function properly it has to hear the room,” says Woolley. “The echo canceller has to build an internal digital model of the acoustics in the room. When you mute a microphone, and it can no longer hear the room, it can’t build that model anymore and it begins to diverge.” ClearOne, however, has solved that problem in its new Converge Pro system. When a microphone button is pushed, that digital model is frozen at the point when the microphone was muted. When that microphone is unmuted, the model picks up from where it left off, rather than having to reconfigure to the acoustics of the room from scratch.

Clear Choice
With as many as 98 Shure MX392C push-to-talk microphones in the largest lecture hall in Kingsville, the Converge Pro technology has proven its worth. “It’s a fairly complex installation,” says Pickrel. “When you’re dealing with that many push-to-talk microphones, you need to have a robust, stable audio processing solution.”

The Converge Pro 880T is the backbone of the audio portion of the system, working in tandem with any number of ClearOne SR 1212 matrix mixers, depending on the number of microphones in a room. All push-to-talk microphones are fed to the eight inputs on each SR 1212, then compressed and routed to the Converge Pro 880T to take advantage of its echo cancellation technology. “We chose ClearOne because they’re the industry leader in digital signal processing products,” says Pickrel.

Conquering Complexity for the End User
All of the new distance learning systems installed in the Health Science Center facilities follow the same basic design, though seating capacity varies. “We are very focused on standardization so the professors have the same user interface, the same look and feel, no matter what room they’re in,” says Pickrel. Each teaching lectern has an AMX touch panel that allows the instructor to control both the distance learning and the local presentation. “We’ve been able to take a fairly complex system, and through the AMX control system, present the end user with a very intuitive, easy to use interface,” says Pickrel. “Then they can focus on teaching instead of the technology.”

Four high definition Tandberg video conferencing cameras handle the video. Two NEC NP4000 projectors hang from the ceiling in the largest lecture hall, which also has one NEC Plasma monitor in the front, two on the sides of the room, and a third in back. “The front screen might have a picture of the far side and data,” says Pickrel. “The two side screens might have the data that serves the outside portions of the room. The monitor in the back serves as a confidence monitor for the presenter so he can look out to the audience and still see what’s being presented on the screen behind him.”

While some of the university’s older distance learning systems still share codecs, rooms and assets to keep costs down, each of these new systems can work independently, calling up to four other locations before using a bridge. “We do have two bridges that enable us to bring in 20 participants each if we need to,” says Alexander. “We use our bridges every day, constantly.” The Right Prescription
By offering such a broad range of curriculum without requiring time and travel of its students, the College of Pharmacy has made it easier for students to specialize. “Do they want to work at a pharmacy, or a hospital, or a doctor’s office?” says Jim Conley, Senior Microcomputer and LAN administrator in Kingsville. “Maybe they want to open their own practice. There are all sorts of things to consider while in pharmacy school, and having distance learning allows the students to take these particular courses to further their own professional education.”

“The key for us has been using features that are required for teaching today and integrate them into the infrastructure of the room,” says Sean Alexander. “The College of Pharmacy in Kingsville has been able to do that very well. We’ve been able to broaden our available pool of good, quality students, because we’re not requiring someone who wants these specialized skill sets to travel, or pick up and move their families. We’ve used geography to our advantage, and we do cover a lot of ground.”