A little bit about the EDACS Systems

The City of Albuquerque and Bernalillo County have three different EDACS (Enhanced Digital Access Communication System) systems. Each System has an ID#.

System #1 is utilized by The City of Albuquerque for Public works. Solid waste, Public transit, Water Department, and Animal Control are some of the agencies that use this system. This is a single site system meaning that there is only one site containing all 15 channels citywide.

System #2 and #3 are strictly for Public Services. Anything that has to do with governmental operations in Bernalillo County uses these two systems. Being that the City and the County is so spread out, the remaining #2 and #3 Systems are a Multi-site and Simulcast System. System #2 has three different sites, and System #3 has four different sites. The EDACS radios are programmed for wide area systems scan operations. Upon the loss of the currently selected system’s control channel, the radio will look for the control channel of the other sites system. Once found, the auto-login of the radio will ping the other system to say that it’s “roaming” and to transfer all of its calls through the other system. Easier understood it’s like a cell phone. If your travel out of your coverage area (Roaming), your cell phone will look for another signal, once found the Other Cellular carrier will transfer all incoming and outgoing calls to your cell pone. Just like a cell phone, the radio will continue to search for its priority systems control channel. Once found the radio will go back to its original system. Albuquerque Police and Fire Departments radios are assigned to System #1, and Bernalillo County Sheriff and Bernalillo County Fire Department radios are assigned to #2. Simulcast involves the simultaneous transmission and reception of identical audio and data information from two or more base stations sites with the same radio frequency to improve signal strength and increase coverage. System #2 has 9 channels, and System #3 has 15 channels.

On all Trunking systems one of the channels is dedicated to the control channel. The control channel is used to send digital information between radios and the computer equipment controlling the operation of the system. All other channels are the working channels used to send the actual voice or data messages between radios, and between radios and dispatch. With the control channel being continuously available, this ensures that call requests can always be accepted. Even if the system has a full load, emergency calls will still go through. Speaking of emergency calls, every EDACS radio has an orange button strictly for the purpose of an emergency. When the button is pushed, the alert shows up on the dispatcher’s console with the radio LID and whose it’s assigned to. With Emergencies in mind, the ECACS radios have the ability to talk on NPSPAC (National Public Safety Planning Advisory Committee) Mutual Aid repeaters and talkarounds. If the Trunk system fails, or Mutual Aid is needed outside of the operational area, the Radios can use Simplex vs. using the trunk systems. Thus turning it into standard analog 800MHz radio that can talk to other 800MHz radios that have the NPSPAC frequencies.

Lets talk about who, and whom we can’t listen to. First the good news. System #1 is 100% analog. WOO HOO! We can listen to trash trucks and the city, falsely reading water meters. Ok, here’s the grim news. System #2, and #3 are almost 100% Digital. The city uses an Ericsson Provoice solution. It is their way of saying “DIGITAL” But not all is lost, some of the dispatches for APD are analog, why you ask? Nobody from the city can answer that for me, but who cares! Also the dispatching intercom for BDFD is in analog too. And recently the janitors at the airport became analog. Remember I said dispatch a few lines ago; the units in the field are all digital. So I repeat this again because everyone gets this so confused. APD, BCFD intercom, and janitors at the Sunport are the only agencies that can be monitored.

Currently there are no SCANNERS on the marked to decode an EDACS PROVOICE DIGITAL SIGNAL! None, NADA, I PROMISE! So the new UNIDEN scanners are out. It can monitor APCO 25 (Association of Public Safety Communications Officials International) Astro Trunked systems with a 4800 baud rate. YES, you guessed it; our system is not APCO 25ish. But who knows, maybe Uniden will come out with a different card to plug in the units to do it. There’s one more thing to a digital signal. Is in encrypted? It is illegal to decrypt an encrypted signal. Some more good news, most of the communications is not encrypted. So again, were all still waiting for a new scanner to come about so we can listen to EDACS Provoice communications? Did I mention how fun it is to collect stamps?

So now there is only one solution left to listen to our Pubic Safety Department. Follow a fire truck around until a radio falls off! That would be sweet. More bad news. EDACS radios have built in security features just for this reason. Should a radio get lost or stolen, the radio can be disabled through the communications system director. How you ask. Just like before when we were talking about emergency calls. Each radio has a LID. Just as cell phones have ESN’s, EDACS radios have their own “ESN.” Every time the radio is turned on, or changes channels, the radio has an auto login feature that pings the system with its LID to alert of its status. The CSD has the ability to deprogram the radio over the air, thus making the radio a useless. But look on the bight side. You are now the owner of the most expensive brick on the planet!


All text Copyright 2001-2003, Erik Conerty - Pictures Copyright 2002, Respective Owners