DMR For Public Safety

[davo51]

I work with several different agencies, city, county, and state. One agency I work with uses DMR, all the others are P25 phase 1 & 2. My portable P25 radio is an APX 8000, my portable DMR radio is a XPR 7550. the XPR is lighter and smaller and works good, my APX is a little heavier, but I prefer the APX and P25 over the DMR, I use a little DMR in ham radio and the sound is good, but I feel the APX is what I want when things get tough and the weather is bad. And yes, I will admit, I have used my radio in a fight when it was the quickest object to defend myself.

 

[Project25_MASTR]

I think points have been well made except for one or two concerning features and infrastructure. While it is true that P25 and DMR are open standards, every vendor is free to implement proprietary features on either one (a big example is the differences between Harris and Astro 25 trunking systems) and as such a system can still be locked out and kept vendor specific regardless of whether or not it P25 or DMR. Also, while DMR does feature messaging, GPS and data services...P25 does as well. DMR and P25 both have IP connectivity. The only real advantage DMR has is in terms of TDMA operation in a conventional channel otherwise they are fairly comparable in features.

 

[RFI-EMI-GUY]

Good points guys! I really appreciate the info and input, I believe I will stay with the P25 route considering that they are built and tested for first responder (specifically fire) environments.


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A properly designed DMR system can outperform P25 for a fraction of the price. P25 radios, even with federal grant money are many more times expensive than the best DMR models.

Unless there is an interoperability requirement that cannot be met using conventional FM mode or a network patch, there is ABSOLUTELY no financial argument that can sway a decision toward P25.



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[KG7PBS]

The TP9300 is a tough portable radio for mission critical communications. Supporting multiple DMR and analog modes, safety-enhancing features, and a rugged, robust design, the TP9300 is engineered to meet the standards of the most demanding industries.

This Radio is the best way for Public Safety to ues

 

[DisasterGuy]

I think points have been well made except for one or two concerning features and infrastructure. While it is true that P25 and DMR are open standards, every vendor is free to implement proprietary features on either one (a big example is the differences between Harris and Astro 25 trunking systems) and as such a system can still be locked out and kept vendor specific regardless of whether or not it P25 or DMR. Also, while DMR does feature messaging, GPS and data services...P25 does as well. DMR and P25 both have IP connectivity. The only real advantage DMR has is in terms of TDMA operation in a conventional channel otherwise they are fairly comparable in features.

What features? I am using Harris radios on Motorola systems and Motorola radios on Harris systems (and a Kenwood on both). Motorola used to push ADP encryption but even that is now open as ARC4 and ships free in every Harris radio.

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[Jay911]

Zac, as much as it pains me to say this (I'm not a fan of DMR for public safety because it was not designed for public safety workloads), if other public safety agencies in your area are using DMR now, if you intend to work with them in the future, it may be in your best interests to look at DMR.

There are people who will tell you that interoperability should be in analog simplex mode, but the reality is that agencies don't always think that through and make provisions for it. They want to exploit all the features of the brand-new bells & whistles they were sold by their radio shop. If there's a chance you will roam into the jurisdictions of these other fire departments that use DMR in your area, or vice versa, and/or if you will work a situation with EMS where you need to communicate other than face-to-face, you probably should consider DMR. You will NOT be able to intercommunicate with any of them if you go P25 - unless they have reserved some analog capacity in their programming to allow for analog interop.

Good for you for researching all this btw. A large P25 system was developed in my area, and several years ago, a couple of fire departments were sold DMR systems by some radio shops. At least one of them it was rumored was told by their salesman that their radios were completely compatible with P25, which is total BS.

 

[RFI-EMI-GUY]

The history of P25 is pretty spotty. If you go back some 20 years, P25 was supposed to solve interoperability problems as well as create a competitive environment to drive high costs downward. In the trunking world (Smart net and Edacs back then) this made sense. Unfortunately both major vendors spent the next two decades selling proprietary trunked systems with a useless P25 CAI feature attached. Interoperability did not improve, prices of equipment and systems skyrocketed. The P25 standards developed at a snails pace, with trunking remaining an elusive bit. Meanwhile DMR was developed in a shorter time, in a more competitive environment and with better performance an features. Want two time slots on a conventional system Bingo! Want systems affordable and scalable from the smallest to largest? BINGO!. Want IP connectivity, multitasking, roaming, encryption? Bingo, Bingo!

Now some of this capability of DMR is under the heavy hands of Motorola, for example AES encryption, but there is competition and Motorola feels it.

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[MTS2000des]

Now some of this capability of DMR is under the heavy hands of Motorola, for example AES encryption, but there is competition and Motorola feels it.

And after seeing, hearing and learning about what is out there in the DMR world at IWCE this year that MSI won't sell in the USA, despite offering it in other (non-US) markets, exist including true digital simulcast, AES-256, and multi-mode operation (yes even P-25 phase 1, NXDN and analog all in one box)...for about 1/3rd of what an MSI solution costs....

It's amazing that the US DMR market is kept back. Hopefully this will change. DMR for public safety? Fair question. The competition around the world have several successful multi-site deployments at far less than what a single site of my Astro 25 7.14 cost to implement.

After seeing the Karios stuff at IWCE...I am amazed at how far behind this market it is.

 

[Project25_MASTR]

What features? I am using Harris radios on Motorola systems and Motorola radios on Harris systems (and a Kenwood on both). Motorola used to push ADP encryption but even that is now open as ARC4 and ships free in every Harris radio.

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RFI mentioned proprietary CAI features each vendor had. Will the systems operate according to the spec? Yes, are their other features that could be used to fully utilize the system? Yes. For example, Motorola's paging feature is proprietary. As is the OTA alias feature. There is also HPD (which isn't seen much anymore due to LTE).


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[bk117]

RFI mentioned proprietary CAI features each vendor had. Will the systems operate according to the spec? Yes, are their other features that could be used to fully utilize the system? Yes. For example, Motorola's paging feature is proprietary. As is the OTA alias feature. There is also HPD (which isn't seen much anymore due to LTE).


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Are the Feds trying to push P25 over DMR?

It is my understanding that the guidelines for federal funding have changed and in order to qualify, the radio must be "equipped" with AES256, but not necessarily used. If this is true and I haven't been misinformed, what does this mean for DMR?

Even though "some" DMR radios can be purchased with AES256, I don't think it's a common option.

Thoughts ?

 

[krazybob]

I personally think that we're dealing with Motorola lobbying, and politics. DMR has better audio quality and is more frequency efficient. It is capable of AES256 encryption. But Motorola has made P25 "the standard" to build on and it is over 20 years old in technology has surpassed it. Go figure. DMR gives you two channels in the space of one P25. So does NXDN which is excellent audio quality. But Motorola doesn't produce an NXDN radio. Kenwood and Icom do but they are considered lesser quality than Motorola. If that's the case why did CalFire and the Forest Service use Kenwood?

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[Jay911]

You guys would have been at home in the videotape era. Beta was the superior format, but the consortium behind VHS marketed it better and it became the de facto standard.

 

[GTR8000]

I personally think that we're dealing with Motorola lobbying

Motorola also manufactures DMR systems under the MOTOTRBO brand name, so they'd be more than happy to take your money either way. And you can bet that if the feds pushed DMR as they do P25, Motorola would see fit to increase the price of their MOTOTRBO offerings.

DMR has better audio quality

P25 Phase II uses the same vocoder (AMBE+2) as DMR, so it's essentially the same audio quality.

and is more frequency efficient.

P25 Phase II uses the same bandwidth as DMR for two-slot TDMA operation, so that's not accurate either. The only argument is that P25 TDMA is not available in conventional, only trunking, so for a small operation DMR has an edge.

But Motorola has made P25 "the standard"

Actually, APCO made P25 the standard for public safety, hence the P in P25, which is fully written out as APCO-25.

and it is over 20 years old in technology has surpassed it.

DMR and P25 are not as dissimilar as you seem to think they are. A P25 Phase II system uses current TDMA technology, same as...you guessed it...DMR. One advantage that DMR has implemented which P25 has not is the ability to have a TDMA control channel. P25 insists on backwards compatibility with older equipment, therefore the control channel remains FDMA.

DMR gives you two channels in the space of one P25.

As stated above, so does P25 Phase II TDMA

So does NXDN

Nope, NXDN is FDMA...one voice path per frequency.

If that's the case why did CalFire and the Forest Service use Kenwood?

Two words: lowest bidder


Facts matter.

 

[RFI-EMI-GUY]

Are the Feds trying to push P25 over DMR?

It is my understanding that the guidelines for federal funding have changed and in order to qualify, the radio must be "equipped" with AES256, but not necessarily used. If this is true and I haven't been misinformed, what does this mean for DMR?

Even though "some" DMR radios can be purchased with AES256, I don't think it's a common option.

Thoughts ?

There is no federal funding for DMR, only for P25. The AES256 stipulation is a recent change required because Motorola was pushing an inexpensive, yet proprietary encryption feature that was thwarting interoperability.

The federal funding does little to close the price gap between DMR and P25. You pay through the nose for P25.

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[bk117]

There is no federal funding for DMR, only for P25. The AES256 stipulation is a recent change required because Motorola was pushing an inexpensive, yet proprietary encryption feature that was thwarting interoperability.

The federal funding does little to close the price gap between DMR and P25. You pay through the nose for P25.

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Agreed!

 

[krazybob]

"The basic NXDN channel is digital and can be either 12.5*kHz or 6.25*kHz wide. 6.25*kHz dual-channel systems can be configured to fit within a 12.5*kHz channel. This effectively doubles the spectrum efficiency compared to an analog*FM*system occupying a 12.5*kHz channel. The architecture of NXDN is such that two NXDN channels, within a 12.5*kHz channel for example, can be allocated as voice/voice, voice/data, or data/data. As of 2012, this capability cannot be implemented in commercially available hardware on simplex or "talkaround" frequencies, but only through repeaters."

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[RFI-EMI-GUY]

"The basic NXDN channel is digital and can be either 12.5*kHz or 6.25*kHz wide. 6.25*kHz dual-channel systems can be configured to fit within a 12.5*kHz channel. This effectively doubles the spectrum efficiency compared to an analog*FM*system occupying a 12.5*kHz channel. The architecture of NXDN is such that two NXDN channels, within a 12.5*kHz channel for example, can be allocated as voice/voice, voice/data, or data/data. As of 2012, this capability cannot be implemented in commercially available hardware on simplex or "talkaround" frequencies, but only through repeaters."

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My complaint about NXDN is that the frequency coordinators have created a situation where there are few contiguous 12.5 KHZ allocations available in some areas. There are plenty of orphaned 6.25 KHZ slices.

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[Project25_MASTR]

Are the Feds trying to push P25 over DMR?

It is my understanding that the guidelines for federal funding have changed and in order to qualify, the radio must be "equipped" with AES256, but not necessarily used. If this is true and I haven't been misinformed, what does this mean for DMR?

Even though "some" DMR radios can be purchased with AES256, I don't think it's a common option.

Thoughts ?

If federal funding is involved, the radio has to meet CAP compliance at the time it was purchased. CAP only certifies P25.

Some DMR manufacturers (Tait, Simoco for example) offer AES-256 encryption but the radios won't qualify for funding on the basis they are not P25 capable.


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[krazybob]

Irrespective of the technical issues it remains my contention that even though there are more efficient technologies now available it's not going to change.

For example as has been pointed out Phase II of P25 now does CDMA. How many entities in the United States do you think have budgets for this change? Now compare that to switching to DMR. My point is that there are technologies availables. I am fully aware that Phase 2 uses the AMBE+2 vocoder. There has not been a rapid switch to phase II P25. Motorola is not likely to upset their Cash Cow. Besides, how many cities, counties and even States are on the verge of bankruptcy? Still! I further contend that this is as a result of Motorola lobbying. Sure, they can raise the price on DMR but that's not the point.

Take for example LA-RICS. They have not had a regular meeting in over a year. They have no money for the project. Not to mention the fact that only half of the city's if even that and the county are interested in joining. One major city, Los Angeles, wants no part of it. Then you have those that are already on the ICIS Network.

Next you have the fact that they want to leverage the public sector 4G LTE network. Really? Do you think that would have worked during Hurricane Katrina? Do you think it will work after a major earthquake and the Los Angeles area? I don't have all the facts about this aspect but on its face it doesn't make sense. Those of us for example that build linked amateur radio systems know not to hold our breath when a major disaster occurs because the public internet will be down. But yet one system after another is employing VoIP technology.

They have been working on Phase II migration for how many years now? By the time they get to Phase II Phase III will already be typed up and cities expected to pay to migrate to it.

Just one man's opinion. The root question was whether or not other Technologies are capable of AES256 encryption and the answer is yes.

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[mikewazowski]

For example as has been pointed out Phase II of P25 now does CDMA.

You mean TDMA not CDMA.