Any thoughts on the statement by the US' DIA Director that Iran received the "SA-20c"? The S-300PMU2 is the SA-20B. Maybe a PMU2 system with more S-400 components?
Iran has recived Customized PMU2 order and Iran side has requested some modification on S-300PMU2 .
When it comes to S-400 ,it is marketing term original designation was PMU3 and after PMU3/S400 was introduced, original pmu2 from 2007 was re-developed from PMU3/S-400 and now these two version are almost the same and can complement each other.
PMU 2 version is only version that can be upgraded to S-400 without changing even one component, now S-400 can be considered as improved PMU2 since as I said original PMU 2 from 2007 is re-developed with S-400 technology .If PMU2 is upgraded to S400 without any upgrades on engagement radar than it would have less range up to 300km because radar max detection range but since tumbstone lunching range is 1000km if you integrate PMU2 in S-400 you are literary converting whole network to S-400 performanse... You can see this in Syria ..instead deploying all S-400, Russians have deployed S-400 and integrate it with S-300.
So S-400 components and PMU2 components are the same in 95%...also you can see most of these components it in S-500...at least in air defense part of s-500 (s-500 is developed from V family not P, and it will be integrated in Russian cosmic defense).
So PMU2 and PMU3/S-400 are almost same in every aspect except in few components like grave stone instead tumbstone..etc, you can see command posts,terminals, administration posts,lunchers on Iran PMU 2 are same as in S-400 ..S-400 has improved missiles but PMU2 can fire it also but as I said with lower range(except if there is S-400 in network )...Now there are lot of optional components you can add. ..radars Gama D,Protivnik ,short range lunchers...basicly everything you see on S-400.
Iran has requested that all components of PMU 2 are most recent and like I said original PMU2 from 2007 is not same as most recent PMU2 , and Iran had some custom requests so I suppose that is reason why SA-20c tag. If you read Almaz-atney chief designers and consultant article about PMU 2 you will find out how PMU2 and S400 are similar, they said that PMU2 started as deep upgrade of PMU1 but latter it end up as technology migration from S400, they completly rebuilt original PMU2 (which was at first PMU1 upgrade )once S-400 was in production ...so we have PMU2 original version and this PMU2 that is latter redesigned to be similar to S-400 as much at it can.
Here is quote about their thechnical discussion ;
"The best technical discussion of design of the S-300PMU2 to date is a recent article by Alexander Ryazanov, Chief Designer, Vitaliy Semenov, Chief Designer, Almaz-Antey, and Dr Anatoliy Sumin, consultant to Almaz-Antey, published in the Russian language Vozdushno-Kosmicheskaya Oborona journal, No 2 . Follow on articles by other authors expand on this analysis Ryazanov state that the S-300PMU2 began as a “deep modernisation” or technology insertion upgrade to the existing S-300PM/PMU1 / SA-20A design, and state trials (Russian OpEval) were completed in 2007. The protracted development of the S-300PMU2 resulted in technology migration from the concurrent but more advanced S-400 Triumf / SA-21. The intent was to maximise commonality in as many components as possible, between the S-300PMU2 Favorit and S-400 Triumf."
So you can see that original version from 2007 that was designated as sa-20b was latter upgraded with technology that became available after S-400 was introduced. And this is most likely reason for SA-20C tag.In short you have as they say protracted developement of PMU2 version with goal to be as much as it can complement with s-400.