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The Enhanced Digital Access Communication System (EDACS) is a radio communications protocol and product family invented in the General Electric Corporation in the mid 1980s.
A young designer, Jeff Childress, created an autonomous radio base-station controller, known as the GETC (General Electric Trunking Card). The GETC was a general-purpose controller with input/output optimized for radio system applications.
Childress and the team demonstrated that a smart controller could be adapted to a variety of applications, but his interest was really in fault tolerance.
The EDACS system architecture supported large communications footprints. By making the GETC's "trunk" among themselves, one GETC per channel, the system was designed to be inherently fault-tolerant. This provided substantial hardware reductions, and the required software efforts yielded a variety of unique features and options.
This was not a new concept in systems design; however, few other teams have embodied it cleanly into such wide distribution.
EDACS was developed in competition with Motorola's Smartnet trunking system. It claimed, and continues to hold, significant market share. GE teamed with Sweden's Ericsson, and the company became Ericsson GE. Later, GE exited the business. Ericsson eventually sold the Private Radio Systems (PRS) unit to Com-Net in 2000, resulting in Com-Net Ericsson. M/A-COM Inc., a holding of Tyco Electronics, acquired the business and technologies in May 2001, including many of the original team members, some of their children, and a few grandchildren who continue to manufacture and support the product family.
EDACS has the largest customer base of any technology in M/A-COM's portfolio (i.e. EDACS, OpenSky, P25 and TETRA). Over 500 large-scale EDACS radio systems have been sold - with the State of Florida being the largest. Hundreds of thousands of radios have been sold to function on these EDACS systems [ citation needed ].
In April 2009 Harris Corporation (NYSE:HRS), an international communications and information technology company, acquired the Tyco Electronics Wireless Systems business (formerly known as M/A-COM).
Software for system managers and radio monitors alike has been developed outside of the vendor. ETrunker is a modification to the Trunker code to work on the EDACS control channel. Users of the software can monitor and log complete system activity. See the Trunker Site for more info.
The first digital voice mode developed for EDACS was GE's Voice Guard, utilizing sub-band coding for its datastream at a rate of 9600 bps. Voice quality was not great, however, with it quickly being replaced by AEGIS.
AEGIS was the second generation EDACS digital voice mode, made once again by GE, with Adaptive Multiband Encoding as its coding scheme. The voice quality was supposedly 10 times better than Voice Guard, but it was still not very great, especially compared to ProVoice.
ProVoice is Tyco Electronics' (formerly M/A-COM, Ericsson and GE) implementation of IMBE digital modulation for radio communications, being the third generation of EDACS digital voice. It is not APCO-25 compliant, but does use the same IMBE vocoder developed by Digital Voice Systems, Inc. (DVSI). The technical difference between ProVoice and the APCO Project-25 standard is how error correction and modulation is provided to transmit the data. [1]
Telephony is the field of technology involving the development, application, and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is intimately linked to the invention and development of the telephone.
Software-defined radio (SDR) is a radio communication system where components that conventionally have been implemented in analog hardware are instead implemented by means of software on a computer or embedded system. While the concept of SDR is not new, the rapidly evolving capabilities of digital electronics render practical many processes which were once only theoretically possible.
In electronics, a remote control is an electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operate devices such as a television set, DVD player or other digital home media appliance. A remote control can allow operation of devices that are out of convenient reach for direct operation of controls. They function best when used from a short distance. This is primarily a convenience feature for the user. In some cases, remote controls allow a person to operate a device that they otherwise would not be able to reach, as when a garage door opener is triggered from outside.
This is an index of articles relating to electronics and electricity or natural electricity and things that run on electricity and things that use or conduct electricity.
Professional mobile radio are person-to-person two-way radio voice communications systems which use portable, mobile, base station, and dispatch console radios. PMR systems are based on such standards as MPT-1327, TETRA, APCO 25, and DMR which are designed for dedicated use by specific organizations, or standards such as NXDN intended for general commercial use. These systems are used by police, fire, ambulance, and emergency services, and by commercial firms such as taxis and delivery services. Most systems are half-duplex, in which multiple radios share a common radio channel, and only one can transmit at a time. Transceivers are normally in receive mode, the user presses a push-to-talk button on his microphone when he wants to talk, which turns on his transmitter and turns off his receiver. They use channels in the VHF and UHF bands, giving them a limited range, usually 3 to 20 miles depending on terrain. Output power is typically limited to 4 watts. Repeaters installed on tall buildings, hills or mountain peaks are used to increase the range of systems.
Project 25 is a suite of standards for interoperable digital two-way radio products. P25 was developed by public safety professionals in North America and has gained acceptance for public safety, security, public service, and commercial applications worldwide. P25 radios are a direct replacement for analog UHF radios, but add the ability to transfer data as well as voice, allowing for more natural implementations of encryption and text messaging. P25 radios are commonly implemented by dispatch organizations, such as police, fire, ambulance and emergency rescue service, using vehicle-mounted radios combined with repeaters and handheld walkie-talkie use.
A mixed-signal integrated circuit is any integrated circuit that has both analog circuits and digital circuits on a single semiconductor die. Their usage has grown dramatically with the increased use of cell phones, telecommunications, portable electronics, and automobiles with electronics and digital sensors.
OpenSky is a registered trademark of Harris Corporation and is the trade name for a wireless communication system, invented by M/A-COM Inc., that is now a division of Harris RF Communications. OpenSky technology applies voice over IP transport to radio communications applications in a unique architecture.
A trunked radio system is a two-way radio system that uses a control channel to automatically assign frequency channels to groups of user radios. In a traditional half-duplex land mobile radio system a group of users with mobile and portable two-way radios communicate over a single shared radio channel, with one user at a time talking. These systems typically have access to multiple channels, up to 40-60, so multiple groups in the same area can communicate simultaneously. In a conventional (non-trunked) system, channel selection is done manually; before use, the group must decide which channel to use, and manually switch all the radios to that channel. This is an inefficient use of scarce radio channel resources because the user group must have exclusive use of their channel regardless of how much or how little they are transmitting. There is also nothing to prevent multiple groups in the same area from choosing the same channel, causing conflicts and 'cross-talk'. A trunked radio system is an advanced alternative in which the channel selection process is done automatically, so as to avoid channel conflicts and maintain frequency efficiency across multiple talkgroups. This process is handed by what is essentially a central radio traffic controller, a function automatically handled by a computer system.
Electronic media are media that use electronics or electromechanical means for the audience to access the content. This is in contrast to static media, which today are most often created digitally, but do not require electronics to be accessed by the end user in the printed form. The primary electronic media sources familiar to the general public are video recordings, audio recordings, multimedia presentations, slide presentations, CD-ROM and online content. Most new media are in the form of digital media. However, electronic media may be in either analogue electronics data or digital electronic data format.
The Technology and Engineering Emmy Awards, or Technology and Engineering Emmys, are one of two sets of Emmy Awards that are presented for outstanding achievement in engineering development in the television industry. The Technology and Engineering Emmy Awards are presented by the National Academy of Television Arts and Sciences (NATAS), while the separate Primetime Engineering Emmy Awards are given by its sister organization the Academy of Television Arts & Sciences (ATAS).
This is an alphabetical list of articles pertaining specifically to electrical and electronics engineering. For a thematic list, please see List of electrical engineering topics. For a broad overview of engineering, see List of engineering topics. For biographies, see List of engineers.
Motorola Type II refers to the second generation Motorola trunked radio systems that replaced fleets and subfleets with the concept of talkgroups and individual radio IDs. There are no dependencies on fleetmaps, therefore there are no limitations on how many radio IDs can participate on a talkgroup. This allows for greater flexibility for the agency. When scanning Motorola IDs, each Type II user ID appears as an even 4- or 5-digit number without a dash.
In telecommunications, APCO-16, is a US standard for the characteristics and capabilities of public safety trunked radio systems.
LTR MultiNet Systems are APCO-16 compliant LTR Trunked Radio Systems and thus are mostly found in use as public safety systems. LTR MultiNet systems usually have one or more "status channels" that act like a control channel in a Motorola or EDACS system, however these channels can also carry voice transmissions simultaneously.
Multi-Band Excitation (MBE) is a series of proprietary speech coding standards developed by Digital Voice Systems, Inc. (DVSI).
Etherstack is a provider of wireless communications software for the Professional/Land Mobile Radio and defense industries in Europe, Asia, and North America. Their products encompass wireless protocol stacks, IP-based communication networks, cryptographic communications, Software Defined Radio (SDR), and Software Communications Architecture (SCA) compatible waveforms.
MACOM Technology Solutions is a developer and producer of radio, microwave, and millimeter wave semiconductor devices and components. The company is headquartered in Lowell, Massachusetts, and in 2005 was Lowell's largest private employer. MACOM is certified to the ISO 9001 international quality standard and ISO 14001 environmental standard. The company has design centers and sales offices in North America, Europe, Asia and Australia.
Electronic engineering is a sub-discipline of electrical engineering that emerged in the early 20th century and is distinguished by the additional use of active components such as semiconductor devices to amplify and control electric current flow. Previously electrical engineering only used passive devices such as mechanical switches, resistors, inductors, and capacitors.