Translation:The country produces good products when it comes to televisions.
What indicates plural is that the word "fjernsyn" stands alone; i.e without any articles and/or suffixes.
The forms of the noun are as follows according to DDO:
Et fjernsyn, fjernsynet, fjernsyn, fjernsynene
The third one is the indefinite plural; it is the only form of the noun that can stand alone without articles or suffixes.
I hope this helps.