The school in the remote town of Assin Foso, Ghana
, might be the last place you’d expect to find a videoconferencing system—for one, there’s no broadband service—but there it is. The story of how it got there
is worth reading for any technology manager faced with projects such as setting up a videoconferencing system on short notice because a science teacher landed a virtual interview with an astronaut.
In late 2011, The Hershey Company began work on a distance-learning project
to connect the Assin Foso school with students in Hershey, PA. The company asked its videoconferencing vendor, Cisco, to help facilitate the virtual classrooms at both ends.
In Ghana, the challenges included:
· Unreliable electricity, which meant scaling back the amount of videoconferencing gear to minimize both the power load and points of failure. For example, the setup uses just one pan-tilt-zoom camera and forgoes an audio mixer, with the mics plugged directly into the codec
. This barebones setup could be a good fit for any classroom where the budget, electrical system or both are maxed out.
· Lots of ambient noise. “Classrooms in Ghana are not in enclosed spaces,” says Ed Schermerhorn, the Cisco TelePresence Systems engineer who spent two weeks in Ghana setting up the system. “Most have only half walls and a roof, so you have no control over acoustics.”
The noise isn’t just from students in adjacent classrooms, either. It also comes from sheep, goats, and chickens grazing nearby. Schermerhorn mitigated the noise by using two low-gain mics and having the students walk up to use them, instead of trying to capture their voices while seated. That’s a viable design for any classroom that doesn’t have a permanent AV system other than the PA.
· No broadband on site. Instead, it’s brought in over a microwave link that consistently provides about 4 Mbps. The system wound up using about half of that speed, which shows that, for example, rural American schools could use LTE 4G cellular
or, eventually, TV white spaces
for distance learning applications. In fact, Schermerhorn successfully used a 128 kbps satellite link for a similar videoconferencing setup in Resolute Bay.
Jitter might be a more important aspect to focus on. “Jitter will kill video,” Schermerhorn says. “It has to be sub-30 milliseconds because at that point, the codecs are going to start discarding packets.”
If there’s one lesson to be learned, it’s that where there’s a will, there’s a way. Often that will can be enough to negate what otherwise look like problems. For example, students and teachers can live with occasional glitches in the video feed if they realize that’s the price of being able to interact with their peers on the other side of the planet.
“You have to balance what the experience is versus the opportunities you’re opening up that otherwise wouldn’t be available,” Schermerhorn says. “I use this now when people say they can’t get a connection. I show them [Assin Foso] on Google Earth and say: ‘I did video here. What do you have that’s more remote than that?’”
Tim Kridel has covered the technology and telecom industries since 1998 for a variety of publications including AV Technology, Pro AV, and InAVate.