Here is a basic breakdown, and due to it being basic will catch heat from SOME here: Top Level Digital Standard - DMR, Can be applied to three levels, or Tiers in the standard, which apply to licensing, and technical abilities. Tier 1, Tier 2, and Tier 3. DMR can be used on VHF High, UHF, 800 MHz, and 900 MHz. I have yet to see it applied to VHF Low yet (Though that could be a future development since they do have P25 on it now.) DMR can be used on Conventional - Simplex, Base/Mobile, Repeater, and a newer format that seems to only be a DMR thing so far - IP Site Connected Conventional (Which is used in the Worldwide Ham DMR set ups like Brandmiester). DMR can be used on Trunking Systems, and here is where the confusion kicks on for many. ***Due to Motorola Solutions literally owning everything about DMR Intellectual Property, everyone refers to anything DMR as "TRBO", short for the Motorola trademarked MotoTRBO.*** And the out of the 4 DMR Trunking flavors we list on the DB, 3 of them are MotoTRBO formats: MotoTRBO Connect Plus, MotoTRBO Capacity Plus, and MotoTRBO Capacity Max. Then there is Tier 3, which can get you confused as MotoTRBO Capacity Max can be configured to use pure Tier 3 standards, or can use certain proprietary standards making it a "hybrid" monster if you will. As for scanners, Uniden paid to fully license the DMR "types" from Motorola Solutions, and passes those costs along to us in the "Paid Upgrade" format, Whistler just puts it directly into the costs of the scanners. If you have a scanner that can do DMR whether it is an Uniden, or Whistler, or other... You can program and monitor Conventional DMR, Connect Plus, Capacity Plus, Capacity Max, Tier 3, and IP Site Connected Conventional DMR. NXDN which includes Kenwood's NexEDGE, and iCOM's iDAS is another Digital Standard and requires another license, thus another upgrade. EDACS ProVOICE is an proprietary digital voice format that only Harris put out and requires yet another license and upgrade. ***This format is officially discontinued and is slowly going away.*** OpenSKY is another digital format completely and again is a Harris creation, and can not be monitored by any scanner, and also is an discontinued format.