Batboard

I'm not sure if it has been discussed, but I have a question about the different manufacturers of current trunk systems. With all the talk of interoperability, why do certain manufacturers continue to push and develop proprietary digital voice formats, or ones that are more expensive to implement? I'm talking of course about ProVoice, and OpenSky that uses TDMA both by MA/COM. Is this maybe something to do with MA/COM on an enterprise level trying to sell "exclusivity" to customers by telling them no one can listen, or do they have other motives? P25 CAI has been around for many years, yet not all manufacturers use it. My thought is that by MA/COM using proprietary voice technology they can then sell their other lines of equipment that interface with equipment made by other companies.

I'm in the market again for scanners, and was looking around a lot today, and picked up most of this information, and also noticed MA/COM also came out with the "ESK" (Electronic/EDACS Security Key I believe, correct me if I'm wrong). Basically it's a code in the radio to be able to decode the control channel to be able to track the talkgroups properly. Some say it's to keep unauthorized users off the system, some say it's to key scanner listeners away.

Motorola could have stuck with VSELP, but decided to go with the open standard.

I know this is a radio board and I don't want to turn it into a scanner discussion so I'll keep it simple. Why the different voice options so long after APCO P25 came out?

LuiePL wrote: Motorola could have stuck with VSELP, but decided to go with the open standard.

And made billions based on that decision!

LuiePL wrote: Why the different voice options so long after APCO P25 came out?

I think it was a combination of short sightedness by other radio manufacturers, lack of engineering resources to dedicate to the initial switchover to IMBE (in comparison to Motorola who can throw a hundred engineers at whatever project they decide) and ultimately the realization that because of the first two points, they missed the gravy train & were left too far behind to make it worthwhile. I'd be surprised if all the other manufacturers combined have managed 2% of Motorola's P25 sales.

The difference between the trunking system's protocol and the voice protocol should be distinguished. A lot of Motorola's digital trunked systems are not actually P25 trunked systems, but Motorola Smartnet/zone/whatever systems that use P25 voice. So, in this sense, the only difference between these systems and ProVoice systems are the fact that the voice protocol is open. The trunking protocols for both are equally proprietary, so the fact that Motorola's systems run P25 voice doesn't help a whole lot as far as interoperability. I am inclined to think that Motorola's marketing and sales departments had a whole lot more to do with their runaway success in the trunking system world than the P25 part.

I do concede that Motorola was the first to develop equipment for actual P25 trunking systems, and for a long time was the only manufacturer that actually made the infrastructure components, so this has certainly put them ahead of the game in that area.

As for why manufacturers continue to push their proprietary formats, you've got me. M/A Com has P25 equipment now, so I don't know why they don't just give up on EDACS ProVoice. This is again another area where Motorola seems to be smarter. I don't think that Motorola really wants to sell you a new Smartnet/zone system anymore--it'll likely be a P25 system.

LuiePL wrote:Motorola could have stuck with VSELP, but decided to go with the open standard.

Please don't call IMBE/AMBE "open" - it is not. You want to use IMBE or AMBE? You *WILL* pay DVSI. End of discussion.

An open vocoder would be something like Speex.

And please don't confuse the vocoder (IMBE) with the protocol (APCO-25): while IMBE is a part of the APCO-25 standard, the APCO-25 standard also specifies modulation format (which Motorola is quite adept at changing: see LSM and Widepulse), the framing format, error correction codes, protocol semantics, and many other items.

DPL wrote:I don't think that Motorola really wants to sell you a new Smartnet/zone system anymore--it'll likely be a P25 system.

Your absolutely right, they don't. Other than upgrades to existing systems (that will even get VERY limited soon), and a few slight exceptions, P25 trunked infrastructure is all you can get for brand new deployments.