New Jersey’s public-transportation corporation, NJ Transit, and PowerTrunk launched the first U.S. land-mobile radio (LMR) network pilot. Authorization from the and Industry Canada for its TETRA subscriber units and base station radio/repeater allowed to partner with NJ Transit on a pilot program to prove the technology’s viability for U.S. use, said Jose Martin, the company’s chief operating officer.
“PowerTrunk is promoting TETRA in the U.S. in addition tosystems for public safety,” Martin said. “For a number of sectors, such as transit or utilities, we recommend TETRA.”
NJ Transit must upgrade its 20-year-old-plus legacy system with a new system that is scalable, said Andrew Schwartz, the transit corporation’s director of radio communications. As a result, they are vetting available digital technology, including a recently completed pilot of Harris’ OpenSky network.
“What we purchase now must meet our needs today and long into the future,” Schwartz said. “So we are looking at TETRA, just becoming familiar with that technology, just as we had done in a previous pilot where we had’ OpenSky.”
Martin said the pilot program consists of a two-site network that includes PowerTrunk, mobiles, hand portables, a line dispatcher and a switch to integrate the legacy VHF system. The company’s system was integrated with an existing computer-aided dispatch system and the company’s PABX/PSTN gateway to support full-duplex, cellular-like communications between cell or public switched phones and PowerTrunk radios. To support data, the pilot operates on leased T-1 line and a private optical fiber backbone with routers configured for Ethernet Layer 2 tunneling protocol.
TETRA, which has not been available in the U.S. until now, supports a wide set of data functionalities, Martin said.
“In transit, for example, I can tell you at least 95% of the subways and bus operators have chosen TETRA in the rest of the world,” Marin said. “The reason is because TETRA is very flexible and is affordable due to the number of manufacturers in the world.”
Schwartz said TETRA and OpenSky both are viable digital technologies that interface with their bus operations’system and provide acceptable voice quality. He said they are still evaluating coverage issues with TETRA, because the architecture on the subscriber side doesn’t provide as much power output in the 800 MHz band.
“So our general view is that with TETRA you would require more radio sites to provide the same level of coverage as with OpenSky and P25,” Schwartz said. “That is something we are still evaluating.”
When it comes to TETRA, there have been few surprises, Schwartz said. He added that IT personnel liked the system and its features, including full-duplex telephone interconnect capability.
“And it was really easy to use,” he said. “It didn’t require much operator training whatsoever.”
The pilot should be completed by the end of February, Martin said.
For more information on TETRA, attend these sessions at in Las Vegas, March 7-11, 2011.