Why are specifications so confusing for DMR

We get lots of questions on this forum and many stem from people just not knowing, rather than being thick, and with digital radio - even people who do know, end up having to actually try things rather than predict them from specs.

What I mean is that virtually every radio manufacturer who does a DMR radio state very similar information - stuff like compatible with Motorola, Mtotrbo (in all kinds of spelling) Tier I and Tier II, slots, colour codes, and things like audio codecs. The trouble is none of this guarantees the ■■■■ things can talk to each other. Even the same brands seem to resist working together. I have Kydera 300 and 880 radios - they even use the same CPS and have virtually identical menus - bar a few extras for additional features on the 880. Yesterday, I got the 300 transmitting to the 880 and a Retevis 82, but NOT a Zaxcom 900. The 900 can talk to the Retevis, but the Retevis can’t talk to any of them. the 880 can hear the 300 but not talk to it - but I have the CPS for both on two screens and the contents are identical. I’m not talking about complex programming but just the same TX and RX frequency, the same CC and TG and Slot. everything nice and simple, yet so frustrating. Even worse, some radios don’t even tell you when they are receiving something. Some have an LED that shows the channel is active, some don’t. Even worse - some radios when scanning show the current channel active, while others don’t. It is infuriating that something so basic gets missed. All the same specs but with enough variation to make intermingling a real dogs breakfast. For a client I have a number of radios on the way. I have read the specs, and they should be compatible with other radios - but it seems amazing to have to actually wait and see? What sort of specification is so lax that it is insufficient to answer these questions?

EDIT - is the naughty word filter in the forum software programmed with very gentle words. D-A-M-N is a very gentle and acceptable word in the UK. Is it much more insulting in the US?

One of the reasons I refer to the DMR standard as incomplete. It’s missing some valuable inter-vendor interoperability definitions and some other features that would greatly benefit the industry. For the most part however, DMR really appears to simply be MPT1328 signaling with two slot TDMA and digital voice. I assume TETRA has a standards test board to prove interoperability on products similarly to CAP testing with P25 which ensures every P25 radio is interoperable to some degree with every other P25 radio and is part of the reason the cost of P25 is so much higher compared to other solutions.

Just my thoughts though. I totally understand your complaints as I’ve even seen them with Simoco and Motorola products not always interoperating correctly at some of the most basic functions.