Also known as: EDACS

EDACS (Enhanced Digital Access Communications System) is a trunked-radio system developed by GE/Ericsson (later M-A-COM). It uses a dedicated control channel that continuously coordinates the system, with analog FM voice or the digital ProVoice (AMBE) option.¹

EDACS uses a dedicated control channel to assign analog FM (or digital ProVoice) channels.

Overview

EDACS is known for fast call setup via its always-on control channel and tightly specified channel numbering. Systems can be wide-area (multi-site) and were a primary competitor to Motorola Type II.

Technical characteristics

Property	Value
Access	FDMA
Control channel	Dedicated, continuous
Voice	Analog FM or ProVoice (digital)

History

Deployed from the 1980s by GE/Ericsson and M-A-COM for public-safety and utility fleets; gradually displaced by P25.¹

Deployment

Legacy public-safety, utility, and transportation systems, some still operating.

Decoding it with GopherTrunk

See the Status page for GopherTrunk’s EDACS coverage (control-channel following and supported voice modes).

Sources

1. Enhanced Digital Access Communications System — Wikipedia, for the GE/Ericsson/M-A-COM EDACS trunking system, its dedicated control channel, and ProVoice digital option. ↩ ↩²

See also

• Trunked radio
• Control channel
• Motorola Type II
• LTR (Logic Trunked Radio)
• MPT 1327

Learn it step by step

• The digital protocol landscape

From the blog

• SDR Internals, Part 10: Protocol decoders & state machines