What is trunked two way radio?

Editors note – If you might have ever used a walkie talkie you will appreciate the technology, you push a button and talk into the radio, you depress the push button and you recieve a communication back, more likely you’ve worked with a conventional system, but to extend the area of the communications or to tap into a mobile phone style structure you will need a trunked system.

Put simply, where a conventional system is limited by the number of users calling on its capacity at the same time, a trunked system allows you to create virtually unlimited users groups and provides the most efficient use of the radio frequencies and channels allocated to a system.

When you place a call on a trunked system, a channel is allocated to all participants, once the call is completed, the channel is returned to the pool for other users. This sharing of the channel capacity increases the availability of the system to all radio users, maximising availability, especially important at times of peak utilisation.

A trunked radio system is configured on the basis that with any given number of users, not all of them will require channel access at the same time, so fewer individual radio channels are required, providing a number of benefits including savings in the cost of channel licences, the ability to accommodate  more users and user groups, the flexibility to configure access between user groups, increased security against eavesdropping and not least, increased availability of the system at all times.

How does a trunked two-way radio system work?

Where conventional two-way radio communications take place on one frequency a trunked system employs multiple frequencies and is able to scan all the frequencies used in the network to prioritise and allocate availability.

A database lies at the heart of a trunked radio system where it controls access to talk groups and the rules applied to individual users and groups at all times. Typically, at least one frequency will be assigned as a control channel to manage the hand-portable or mobile in-vehicle radios telling them which frequency to monitor for incoming and outgoing transmissions.

When a user makes a call by depressing the Push-To-Talk (PTT) button on their handset, the control channel will automatically find and allocate a free channel and send a message to the radio units involved in the talk group instructing them to change to the free channel. This means a conversation can take place via any available channel rather having to wait for a particular channel to be available.

The control channel is a vital instrument in the seamless management of a trunked radio system, ensuring seamless operation in all situations. It can be used to transmit small data messages between radios even if all other channels are occupied and it provides pre-emptive call handling to ensure radio access in case of emergencies.

When renewing your analogue trunked radio system or upgrading to a digital trunked system, you should specify it to include a dedicated control channel which offers better resilience and the ability to send messages even in the event of equipment failure.

What equipment is required for a trunked digital two-way radio system?

In its most basic form, a digital trunked radio system will comprise of:

– A PC (system manager) to manage and configure the systems’ software and network operation (this is only required for configuration).

– An Ethernet Switch link to a base station repeater.

– Base Units (Up to 30 in per site).

– An antenna system to provide radio coverage.

– Hand portable walkie-talkie and/or in-vehicle mobile units deployed in the field.

Systems requiring more channels (more user groups) will feature additional base units/repeaters or where increased range is required, for example in a regional, national or international network, the system manager could be fixed to an IP connection to link up to 48 digital trunked sites together for wide area roaming and calling capabilities. There are many companies specialising in the design and installation of bespoke private digital two-way radio networks,

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Motorola Solutions’ RhoMobile Suite to Support Johnson Controls’ North American Service Mobility Strategy


Mobile solutions, as it is now known now have released the RhoConnect Platform that links everything to one another, it seems that this is the way ahead for most businesses lately with all devices connecting to each other, but not to other manufacturers. If this kind of technology comes to radios, then it will be a great turning point for this industry.


SCHAUMBURG, Ill. – Feb. 26, 2013 – Motorola Solutions, Inc. (NYSE: MSI) today announced that Johnson Controls, a global leader in delivering solutions that increase energy efficiency in buildings, is using Motorola’s award-winning RhoMobile Suite to create a highly flexible, mobile work environment and make cross-platform application development easier. 

The RhoMobile Suite is the only true HTML 5 cross-platform development framework on the market that brings together a consumer-style application experience with an enterprise-grade feature set. You get the freedom to choose the device that will best serve each job or even bring your own, since one application version runs on many operating systems (OS) and types of devices. By leveraging RhoConnect and RhoElements, part of the RhoMobile Suite, Johnson Controls enables its field service workers to use its mobile applications anywhere, anytime.

As new OS versions become relevant for their various applications, Johnson Controls will be able to quickly add support for a new OS or device without having to change the underlying business logic. 

Johnson Controls has one of the largest technical service organizations in North America. Its workforce is trained and equipped to deliver increased energy efficiency, lower operating costs and provide improved operations in buildings. The new mobility enhancements will improve the customer experience by streamlining the flow of information delivered to technicians, such as service history and asset information. The portable, connected devices provide technicians with an advantage by giving them access to a growing list of applications, such as technical documentation and Global Positioning System (GPS) route optimization apps. 

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Review of the DP 3400

We are grateful to be able to review the Motorola DP3400 2 way radio, this has been on the market for a while, but over the last few years you would have seen this radio used in many shopping centres, office buildings and venues across the UK.


There’s quite a lot that makes the DP 3400 more than just another two-way radio. For a start, the DP3400 employs a single-site trunking solution that can allow over a thousand users to share information, and even data, with each other, without adding new frequencies.

The DP 3400 also comes complete with an emergency button, this button, when pushed, automatically alerts the supervisor (or dispatcher) to any possible trouble without the user having to speak even a single word. Such a safety feature works in tandem with the DP 3400’s ‘Emergency Signalling’ capability, a function that will send an emergency signal to a pre-determined person or group.

The DP 3400 is capable of signal migration for both analogue and digital signals; it easily (and handily) combines traditional radio technology with cutting edge digital methods.

The radio comes in both UHF (4w) and VHF (5w).

This model also comes with a cradle that charges your battery for you, it is an excellent charger, representing an efficient design and complete user-friendliness.


This is a neat little gizmo, but Motorola know that. The price of £350 might seem a little steep at first, but if its professional quality you’re after, then you should be prepared to pay a professional price.


Despite having a decidedly utilitarian feel overall, the outer design actually benefits from a softer, ‘sanded down’ finish. With smoother edges and a more contemporary feel, this two-way radio doesn’t seem as Spartan as a more military or security-centric model might. It provides all the same functions, but the end result is a little bit more aesthetically pleasing and somehow more reassuring. In short, this model will be better for business.

The brightly lit buttons are also very useful if you’re using the radio at night. It’s a Tricolour LED, so the lights appear modern and pleasing.

This is a very tough little device, with a sturdy outer casing and what appears to be shock proofing all the way around. The body of this radio is so well sealed that not even a particle of dust or grit can penetrate it. It can even be fully submerged in water for 30 minutes without succumbing to permanent damage.

The belt clip is sturdy and holds the radio to your belt so well, that you never fear it will fall off. You also get a dust cover, which protects the open accessory port in the event that you aren’t using any accessories. This is a welcome feature that is always nice to see. The addition of programmable side buttons is also a very welcome feature of the DP 3400.

The DP 3400 also benefits greatly from a very long battery life, which is ideal for outdoor work.


This is a marvellous radio. It is suitable for any number of events/functions. The sound comes through clearly, the large microphone/speaker setup allows for ease of use and the entire package is exceptionally well made. The DP 3400 is smart, user friendly and very high quality.

The only knock I’d give it is that the battery, although excellently designed, is somewhat heavy. That’s it.

However, I still think that the aforementioned episode of ‘Spaced’ would have gone a lot more smoothly if they’d invested in a couple of these little beauties.

The impressive Motorola DP3400 radio can be found on this website www.2wayradionline.co.uk

What Should One Be concerned about When Getting a Walkie Talkie For Company Use?

Buying a radio structure is a sizable expenditure for any company, large or small and, as a result, it is crucial that the customer makes the right choice.

Claire Davies, of eZine Articles.com says,

“Purchasing two-way radios for commercial or personal use can prove to be a wise investment for anyone wanting a reliable cost-effective communication system. BUT, the decision as to which radio is right for you requires careful consideration”. Continue reading

ID-51E D-STAR Dual Band Portable Radio with Built-in GPS, Available Now!


The ID-31E was a beautiful diminutive 2 way radio, but that is superseeded by the ID-51E D-STAR now, adding an incredible five hundred further radio channels, missing that important message would not be a problem.


Icom is pleased to announce that the new ID-51E Dual Band D-STAR handportable is now available. Evolving from Icom’s popular ID-31E D-STAR portable, the ID-51E possesses new features including dualwatch, 500 extra memory channels (for a total of 1,752 channels), automatic position reply (DV), repeater search functions and AM/FM Receivers. Continue reading