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You Can Hear Them Now - Oregon Caves National Monument Upgrades Communications with the Underground


Heated, sealed enclosures protect the new cave phones from moisture. NPS photo.

If you're running public tours in a cave, it's always a good idea to be able to communicate with people on the surface, and vice versa. The staff at Oregon Caves National Monument can do so a lot more efficiently these days, thanks to a recently completed upgrade of the communications system in the cave.

The eighteen-month project replaced a deteriorating, stand-alone intercom system, and before starting on the work, the staff did their homework. They evaluated a variety of options for this upgrade, including radio and copper-based systems, and worked closely with Mammoth Cave IT specialist Patrick Price to design the system. Caves pose some special challenges to any electronic devices, due to the damp environment, and there are obvious limits on routes for running cables.

The new system enhances staff and visitor safety and the management of in-cave emergencies and incidents with several significant improvements. The upgrade increased the number of phones stations from three to seven—a phone for every tenth of a mile along the tour route. Normal two-way phone communication, something we take for granted, is now possible. With the old system, calls could only be placed to a single phone in the visitor center.

Programming capabilities, using Voice over Internet Protocol (VoIP), allows all phones in the cave to be dialed simultaneously, an important plus in event of an emergency. The sets in the cave can be programmed to ring a distinct tone to phones on the surface, so calls coming from down below can easily recognized by the staff topside.

The new system is also expandable, making it possible to add phones or other network devices such as cameras or data loggers for environmental monitoring. Three monitoring stations have already been set up to log temperature, humidity, stream depth, wind speed, and other parameters that can be accessed real-time over the network. The park has also obtained an infrared camera for monitoring roosting bats. Eventually this live data will be available to the public through visitor center displays and/or the web.

Safety for visitors is always a consideration, and good communications are an important element in that program. Tours at Oregon Caves are perhaps just a bit more challenging than those in some other sites. The park website notes,

The cave tour lasts 90 minutes, is considered moderately strenuous, and is not recommended for people with heart, breathing, or walking problems. The half mile route includes more than 500 stairs (most of which are steep and uneven) and a total climb of 230 feet. The lowest passageway visitors have to duck under on the tour is about 45 inches tall, and there are many places where bending while walking is required.

As the accompanying photo shows, Clark Kent won't be able to make a quick change in these special "phone booths," but when reliable and prompt communications are necessary, life in the underground has gotten a whole lot easier at Oregon Caves.


As a Ranger that worked at Oregon Caves I'm very glad to hear they've updated the old antiquated communication system.

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