in czechoslovakia, you couldn't dial international calls directly. you had to go to a post office and ask for your call to be connected for you.

if you wanted to make a call to a western country, you had to go through all sorts of "legal" hassle and explain who you are calling to and why. chances were that you got automatically marked as a suspect/collaborator during that process. if you were lucky enough and got connected, the prices were exorbitant. needless to say, the call was usually monitored.

but the common folk didn't simply know any foreign telephone numbers in the first place. most families didn't own a telephone anyway. however, some people had family members abroad, so they did get the chance to talk to them occasionally.

snail mail was a bit better off, but it could be a trial-error endeavour as all mail was subject to random (as well as targeted) checks/censorship by the ministry of interior.

as for other media, you could try tuning in to foreign radios, some of which were specializing in broadcasting for the communist countries (such as Radio Free Europe or BBC World Service) but these were typically subject to radio jamming.

German and Austrian TV was a thing in west and south bohemia, but the signal was very bad as the czechoslovak national TV programme was intentionally broadcast at interfering frequencies.

there were western magazines and catalogues circulating among friends and families. those were like the holy grails of that era (especially the catalogues with all the western goods and variety that seemed almost unreal).

last but not least, there was the "samizdat". a clandestine printing and distribution system for books and fascicles by authors otherwise banned and persecuted by the totalitarian system.

all in all, any contact was rather severely limited. unless you were an active dissident or well-connected intellectual, you knew next to nothing about the western countries. except that they were wealthy capitalist pigs (as the propaganda went ;).