MY understanding is that people use the terms MOD1, MOD2, and MOD3 to describe CCR training. But, I am not sure if any agency actually issues a cert using those terms. I.e. I don't think TDI issues a card that says MOD1 on it.
Somehow can correct me if I'm mistaken but I believe back in the day MOD1, MOD2, MOD3 were what IANTD referred to their CCR courses as. A lot of people have kind of adopted that those names. E.G., if someone saying they are doing a MOD2 course it's pretty obvious that they're referring to normoxic trimix. I'm not 100% sure if this is/was a strictly IANTD thing but that is where I see it most often.
I believe RESA and RTC also uses or used to use the same terminology.
Standards | Rebreather Training Council
https://www.rebreather.org/wp-content/uploads/2018/11/RESA-_mod-2-3.pdf
MOD1- Module 1: Air Diluent or Air Diluent with decompression (30-40m)
MOD2- Module 2: Normoxic Trimix CCR (60m)
MOD3- Module 3: Hypoxic Trimix CCR (Full Trimix 100m)
IANTD doesn't seem use these terms anymore but old habits die hard and people still use them to refer to most levels of CCR training from any agency.
Of course there are now several in-between courses that MOD1, MOD2, MOD3 don't exactly describe this nomenclature.
There is air diluent with or without decompression, there TDI Helitrox or IANTD ART (Advanced Recreational Trimix, there now also IANTD Normoxic+ (Normoxic Trimix to 70m). There is also "Expedition" Trimix which I "guess" is 400ft/120m
Do you know which agencies put the Unit name on MOD2/3, cave etc and which doesn't?
My MOD1 cards (from IANTD and TDI) are both unit specific and list rebreather names (rEvo / SF2). My MOD2 (Normixic Trimix) is from TDI and specific to the rEvo. My Cave CCR and MOD3 (Hypoxic Trimix) were non-unit specific. I have CCR Cave cards from IANTD and NSS-CDS and neither of them list a unit name (non-unit specific)