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Presque Isle Police Department 

Converts to Digital Radios


New Format Off-Limits to

Conventional and Digital Police Scanners


By: David Deschesne

Fort Fairfield Journal, February 22, 2012

PRESQUE ISLE, Maine—The Presque Isle Police Department (PIPD) has updated its radios to narrow-band capability, as per Federal Communications mandate. In addition to upgrading to narrow-band, the police department also opted for a form of digital communications known as Time Division Multiple Access (TDMA).

TDMA is a form of communications that splits up the time on a transmitting channel, allowing additional users on the channel at the same time, similar to technologies adopted by cell phone manufacturers.

According to Aroostook Technologies, Inc., in Presque Isle, the company who installed the radios, the specific format is Motorola’s X2 TDMA.

Because of the change in formats, PIPD transmissions will no longer be able to be received on conventional police scanners. The Presque Isle Fire Department is also planning on using the police department’s digital repeater.

Current “digital-ready” scanners are only capable of decoding the more common Project 25, or P25, digital signals and cannot decode TDMA.

“Presque Isle police and fire departments will be utilizing the digital format on each of their primary frequencies, and they also may use it on certain tactical frequencies as well,” said Kevin Robinson, president of Aroostook Technologies. “They will continue to operate in the analog mode when communicating with outside or mutual aid agencies. As far as I know, the majority of the city of Presque Isle, police and fire departments’ communications will be in the digital mode, but they will continue to page out for calls for the fire department in analog mode.”

Analog mode is the format currently used by police band radio scanners.

In addition to converting to digital, which would have made their transmissions off-limits to all current analog transmitters and all P25 compliant digital scanners, the PIPD also decided to adopt a covert, paramilitary style encryption system to hide all of their communications and intentions from the general public. This encryption effectively prohibits any X2 TDMA digital scanner from receiving their signals under any circumstances.

Presque Isle Police Chief, Matt Irwin was asked by this writer to explain the motivations of the PIPD to convert to the covert form of communications, but received no response.

Critics of the upgrade have suggested that under the older, analog radio systems, or non-encrypted digital, officer behavior and radio etiquette was kept in the open and in check by the constant ability of the general public to monitor their communications on police band scanners. It also allowed the public to be informed about the goings-on in their community and how police officers responded to them. Now, with the adoption of a covert, paramilitary style encryption system, shielding and sequestering their behavior from the watchful eye of the general public, Presque Isle’s officers may be less likely to uphold the same standards they did when they knew they were being scrutinized by the general public monitoring their communications with conventional police band scanners.

Chief Irwin was asked to explain how he would alleviate these concerns, but did not respond.

Currently, there is only one scanner on the market that can decode non-encrypted X2 TDMA digital signals, the GRE PSR 800. However, it cannot decode the encrypted signals used by PIPD and PIFD.

The PSR 800 is available in handheld format only. Unlike other handheld digital scanners, the PSR 800 has a plain front panel layout, similar in function to an MP3 player. It comes with a memory card loaded with all emergency and law enforcement frequencies in the United States and the user merely has to select which State and County they would like to monitor to access those frequencies. The included software also allows the user to input custom frequencies and modes with the use of a computer.

“Our firmware and library updates are all done through the software included with the PSR-800. The library (frequency) updates tend to be on a weekly basis which is gathered from ,” Jon Williams, sales representative from GRE America told the Fort Fairfield Journal. “The firmware updates are a little less frequent but I still recommend running a check for updates for both the firmware and the library at least once every couple of weeks. This will insure that you have the most current information available.”

Another form of TDMA, called Phase II TDMA is being developed which the PSR 800 currently may not be equipped to handle. “We are capable of decoding X2-TDMA, however, Phase II TDMA is currently not live yet so we have no way of testing it,” said Williams. “Phase II TDMA is currently still in testing so there are no active frequencies. Once there are active frequencies in Phase II TDMA we will be able to begin our testing to see if our scanners can support it.”

Williams is surprised that a police department the size of Presque Isle’s would have adopted the military-style encryption format. “That is quite interesting. Presque Isle does appear to be the largest city in Aroostook County but still not the largest in Maine. I would have imagined an area like Augusta would go encrypted but not Presque Isle,” said Williams. From what I’m gathering some police departments are considering switching to full encrypted but it’s not something that is confirmed at this time.”

Williams says at this time there is nothing his scanner can do to decode an encrypted frequency. “I do apologize for this inconvenience.”

Currently, Presque Isle is the only police department using encrypted digital in Aroostook County. According to Robinson, from Aroostook Technologies, others are considering it. “I’m not sure if other departments will go digital or not. We are talking with other customers about this format, but it’s too early to tell if they will convert,” he said. “Public safety departments do like the encryption features for the privacy aspect.”

Robinson says Caribou Public Works is also using the same type of digital system.

For more info on the GRE scanners for non-encrypted digital reception, go to: 


March 21, 2012 - Presque Isle Police Chief Responds to FFJ Digital Radio Story



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