Did the soviets have those facilities ?
I don't know. They knew about the US system, and the technology was certainly within their grasp if they decided to go down that path. But you have to remember that the USSR existed in a very different strategic environment to the US, and it had its own ideas about how to use strategic assets like SSBN. They conducted much shorter patrols for one thing, and didn't go as far afield. So while I'm sure they had some means of contacting their SSBN, I'm not sure it was ELF.