Full Time 4WD System in Lada 2121?

This question may be pretty well "off topic" for North Americans but I see a lot of Lada 4x4s where I live (Nivas and 2121s). According to "wickipedia" production began in 1977 and and the vehicles were equiped with full time four wheel drive using an Aisin transmission and/or transfer case. Well that´s what I read...Can anyone elaborate on the four wheel drive system of the Lada? Was it like the New Process 205 transfer case used on early 70s American 4x4 pickups employing a chain drive or something else?