Trunking Communications Monitoring (Autumn, 1998) ------------------------------------------------- By TELEgodzilla The powerful marriage of computers and radio communications created a new child of the twenty-first century: trunked radio systems. Trunked radio communications allot multiple users to all available channels/frequencies through a series of user programmed controls. Conventional radios traditionally limit user access to their assigned channel grouping (channel 1 to repeater 1, channel 2 to repeater 2, etc.). Whereas trunking allots full implementation of all available channels' frequencies at any given moment while yet allowing full system programming. Note how the term "trunking" is used: it's from (you guessed it) telephone trunking. In trunking, "talkgroups" (groups of radios programmed to speak to one another) are the norm. Individual radios are programmed via a typical PC (usually a laptop to allow for ease of portability). Each trunked radio holds a computer chip allowing for a "personality" programming. Groups of radios can be programmed by creating "profiles" usually in minutes - and rapidly duplicated or, if need be, individually tailored. System users, thus, better employ the number of channel sets their overall system employs. In many instances, a typical trunked system can carry over 3,000 user-specific talkgroups allowing for several hundred radios to be assigned to each individual talkgroup. Trunked communications employs precision computer control, enhancing system efficiency. Trunking controls to whom and for how long each user can talk as well as the priority each user possesses. "Dumping" or "crowding" is far less likely to occur on a trunked radio system than any other and waiting time is dramatically reduced. Users are "queued" and stored in memory. Users with higher priorities are enabled to be put on the air quicker than others (based upon how the radios are programmed) while data communications (depending upon the model of the system) functions on background operations. Trunking also allows a system overseer to turn off a (or several) radio(s), should it/they become lost or stolen. When recovering a trunked radio, enjoy it while you can; it generally doesn t take long for that radio to become a useless paperweight with the flick of a remote switch at the System Controller. Security is enhanced. Digital trunking systems enable full digital communications, ensuring against eavesdropping. Depending upon the make - Motorola and Ericsson are the two top contenders (E.F. Johnson also makes a conventional trunked system, but they re having problems with their design) - there are different approaches and points to consider. Motorola: Smartnet and Astro Motorola's two primary trunked systems - Smartnet and Astro - are worlds apart. Smartnet is junk; a recent State of Hawaii court ruling illustrated that Motorola's Smartnet is not, as so defined by trunked communications requirements, a true trunked system (which goes to show that when buying Motorola, stick with their pagers). Agencies using Smartnet can be readily breached via a typical trunked scanner (also known as trunk trackers). Some recommended models are the Uniden Bearcat BC235XLT (handheld) or BC895XLT base scanner), assuming that the Smartnet system in question is actually functioning. There have been a growing number of localities who've had their Smartnet systems ripped out and replaced. Astro is a tougher nut, but not too many organizations use this system as Astro is expensive and is non-compartmentalized; in other words, when you buy an Astro, you gotta buy everything at one time. Unless an organization has a couple of million to spend every time it needs to upgrade or expand, this is not an economically viable system to obtain. Ericsson: EDACS Ericsson systems are choice; if you want a good, reliable system for a decent price and one that'll keep out the weirdoes, get an Ericsson EDACS system. EDACS (Enhanced Digital Access Communications System) is used by the Secret Service Presidential Bodyguard as well as the U.S. Navy's Carrier Strike Force s ship-to-ship communications backbone, and is currently used by Boris Yeltsin's bodyguards. EDACS has been used in Bosnia by U.S. forces because they truly meet military specs, designed to be tossed out the back of a C-130 (via parachute, of course), and ready to be deployed in minutes. EDACS can also be readily enhanced for specific parts or services; one need not buy an entirely new system when you got EDACS. Ericsson systems use AEGIS encryption. Forget about trying to crack AEGIS; it's NSA (National Security Agency) rated and unless you got heavy iron with massive power and time on your hands (and I mean lots of time), you ain t gonna crack it - period. It's not surprising that the feds are always assigned at least one radio to keep their hand in the action, no matter how small or insignificant the locality's trunked radio system is. Don't waste your time; it's not enough to obtain the algorithm as AEGIS is fully digital and unless you have full physical access to the System Controller, you can't listen in. Trunked radio systems dedicate one frequency out of their total set for the control channel: this control channel constantly transmits each and every transmitter/receiver's own unique programming, thus locking out anyone from "stepping" on the frequency set. If you do tune into the control channel, all you ll get is a rapid sledgehammer sound effect and quite possibly a busted speaker (and headache) if you have your volume up too loud. Accessing it won't do you any good. All is not lost, however, as encrypted radios are not cheap. They usually go for about $2,000 apiece; most private and public entities, therefore, use the regular unencrypted communications, allowing listeners to employ trunk trackers with no problem. When monitoring trunked systems, remember that you first need to know the frequency set that the system is using. This can be achieved by contacting the FCC and obtaining a listing of frequencies that are being used; this is, after all, public information. Other frequency resources to consider are the Pocket Guide series of frequency directories for selected portions of the United States. Trunked trackers can be readily purchased for as little as $150 on up, if not cheaper. Make sure that the frequency set you wish to check out is carried on the tracker of your choice. Some systems will defeat the trunk tracker, however, by setting up a "tail" - the end of the communications broadcast to hang a second or two longer; this confuses the tracker and makes it hard to listen in on the action. Many radio managers don't do this kind of thing as this, however, would involve prescience and intelligence on the part of managing a radio system. As with most hierarchical structures, radio controllers tend to be awarded on the basis of obedience and trust, not necessarily of intelligence and initiative. Utilities (read: telephone), oil refineries, airports, police, fire, and paranoid private/public security forces are among the primary users of trunked systems. Trunking enables system deployers to request a minimal number of frequencies which, through the enlightened vision of our FCC, often costs a lot of money or requires a tremendous waiting time. There are also conventional trunking systems, which piggyback onto regular radio systems; a typical trunk tracker can, however, handle these with no problem. Radio communications carry a lot of information and trunked systems are the coming wave!