To view some of the digital models we sell, select from the following:
In the same way that analog mobile phones were gradually replaced by the more feature rich and secure digital phones, and that digital television is set to make analog television redundant, so too the radio communications industry is experiencing the same paradigm shift.
Analog radio technology has advanced to the point where it is beginning to approach its own limits. As networking and telephony technologies advance at an exponential rate, radio technology must keep up, get ahead or also be rendered obsolete.
Digital radio is here to stay, but the technology is still maturing. In these relatively early days, many manufacturers seem to be trying to set standards rather than follow them, and while most vendors are doing their best to keep their systems compatible with the other systems out there, many are still bringing out new (and therefore proprietary) technologies to address the industry's needs. As is to be expected, different manufacturers find very different ways to solve certain problems. Some solutions are more elegant than others and prevail by their own virtues, others are just marketed better and we the public get a raw deal when everyone adopts the lesser technology as the de facto standard.
This situation is very well demonstrated by the rivalry between manufacturers of Betamax and VHS video tape technologies. Arguably Betamax was the superior technology, but VHS won the day through superior marketing, and we the public got stuck with something that was less than best.
So far this is what the Digital radio landscape looks like:
APCO Project 25 (P-25)
A whole bunch of firemen, police officers, ambulance officers and other public safety types, through the Association of Public Safety Communications Officers (APCO), sat down and decided what they needed their radios to be capable of. The set of standards that emerged is now called P-25 and is still very relevant even 20 years on. Most manufacturers make a range of P-25 compliant radio transceivers. P-25 however needs to advance so as to keep pace with developments in other digital modes; already some headway is being made into Phase 2 of the P-25 standard, but this phase is still a long way from being completed.
TETRA (TErestial Trunked RAdio)
Formerly known as Trans-European Trunked RAdio, and also with its roots in public safety organisations, TETRA is a European Telecommunications Standards Institute (ETSI) standard, first version published 1995. TETRA uses Time Division Multiple Access (TDMA) with up to four user channels on one radio carrier and 25 kHz spacing between carriers. Both point-to-point and point-to-multipoint transfer can be used. Digital data transmission is also included in the standard albeit at a low data rate.
TETRA is the basis of many wide-area networks such as Motorola's Zeon Network, and it is gathering momentum. Whether TETRA becomes the de facto standard or simply remains as one of many competing standards is yet to be seen.
NEXEDGE and IDAS
As with TETRA, Kenwood's NEXEDGE and ICOM's IDAS offer wide-area networked trunked radio systems but theirs is based on the NXDN protocol. NXDN uses Frequency-Division, Multiple-Access (FDMA) technology in which different communication streams are separated by frequency and run concurrently. FDMA offers (at the moment) higher rates of data transfer for digital radio, but there are also limitations (such as crosstalk and interference).
What digital radio offers you:
Digital radio offers many (most) of the features offered by analog radio, but it does so with greater efficiency and therefore with better results. Obviously the security of digital radio makes it a highly desirable medium for Transport, Police, Fire, and Emergency operations, but more and more users are turning to digital if only for its superior audio quality (even in weak-signal environments). The audio with analog radio decays as the signal weakens, to the point where the noise overcomes the signal. With digital there is no gradual drop off. If the signal is above a certain threshold the audio will be good; unfortunately the downside of this is that below that threshold there is nothing. In reality though, the threshold in which digital cuts out is well below the threshold where analog stops being useful. Digital systems also offer improvements in the way group calls, individual calls, messaging, GPS location etc are handled.
Most digital radios retain their analog capability and can operate in either mode as the situation demands. This allows users to phase their migration from the older (legacy) analog systems to the newer digital technology, any by doing so keep costs under control.
Talk to us at COMMEX about how you can get the most out of your current systems while still taking advantage of the new technologies (and features) as they become available. Some of the digital radios we sell are shown below. Click on any to see its specifications pricing and what peripherals are available for it.
Or simply Contact us and let us take the guesswork out of it for you.