Enhanced Digital Access Communications System (EDACS)

Enhanced Digital Access Communications System (EDACS)

Frequencies	160 MHz,450 MHz,700 MHz,806 MHz,870 MHz,896 MHz,941 MHz
Frequency Range	160 MHz - 941 MHz
Mode	NFM
Modulation	GFSK
ACF	edacs48: 60 ms, edacs96: 30 ms
Emission Designator	—
Bandwidth	12.5 kHz,6.25 kHz
Location	Worldwide
Short Description	EDACS is a trunked radio system developed by General Electric and Ericsson. EDACS was invented by General Electric in the mid-80s and is currently owned by Harris Corporation. Harris has announced that EDACS systems will no longer be supported by 2017.
I/Q Raw Recording	Download file
Audio Sample

EDACS is a trunked radio system developed by General Electric and Ericsson. EDACS was invented by General Electric in the mid-80s and then further engineered by Ericsson and is currently owned by Harris Corporation. Harris has announced that EDACS systems will no longer be supported by 2017, urging customers to switch to newer P25 systems.

EDACS is primarily seen with its trunking channels; the voice can either be analog FMFrequency Modulation or digitally encoded with AEGIS or ProVoice. AEGIS was the original format, but was soon replaced by ProVoice.

EDACS has three modes, Wideband, Narrowband, and Encrypted. Wideband EDACS is the most common form of this channel, and uses a 12.4kHz wide 9.6kbit/s trunking channel segmented on 25 kHzKiloHertz (kHz) 10^3 Hz wide channels, where Narrowband EDACS uses 6.25 kHzKiloHertz (kHz) 10^3 Hz 4.8kbit/s trunking on 12.5 kHzKiloHertz (kHz) 10^3 Hz wide channels. The Encrypted version of EDACS (called EDACS Security Key (ESK), M/A-COM's trademark name for this feature) is a variant of the Wideband EDACS format, using specially coded frames that require a specific security key for two EDACS radios to communicate.

Transmitted using GFSKGaussian Frequency-Shift Keying digital modulation over working channels at either 4.8kbit/s or 9.6kbit/s. EDACS is a type of ESMR (Enhanced Specialized Mobile Radio) network.

Samples

EDACS 4800	EDACS 9600	EDACS Fire Disp. Callguard	Analogue FMFrequency Modulation Voice

Frequencies

Frequency bands: 160 MHzMegaHertz (MHz) 10^6 Hz, 450 MHzMegaHertz (MHz) 10^6 Hz, 700 MHzMegaHertz (MHz) 10^6 Hz, 806 MHzMegaHertz (MHz) 10^6 Hz-870 MHzMegaHertz (MHz) 10^6 Hz, 896 MHzMegaHertz (MHz) 10^6 Hz-941 MHzMegaHertz (MHz) 10^6 Hz

Decoding Software

Hobby Level Software

• Unitrunker.

Decoding Tutorials

• Following trunked radio with the RTL-SDR

Additional Links

• EDACS End of Life Announcement
• EDACS info
• ESMR Definition
• Introduction to Digital Professional Mobile Radio: EDACS
• EDACS White Paper
• Radioreference.com EDACS
• RadioScanner.RU EDACS-4800
• HFAsia EDACS
• EDACS and ProVoice system information

Additional Images

Spectrogram showing the EDACS GFSKGaussian Frequency-Shift Keying waveform. The frequency shift is about ~2825 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).. Example of EDACS and Provoice trunking system in Florida.