Well, I was recording with my Technics cassette deck and my cell phone rung. The phone was resting very close to the deck (how stupid I was!!!). But I didn't heard any interference. So, I guess it's shielded. This particular deck is an RS-B965. It was made at the early '90s when most devices of that era weren't designed to be immune to cell phone interference. Furthermore, I remembered that I never had heard any from my other Technics decks (of the same era). And that's strange as I can hear this interference on some more recent devices (like TV sets and amps). To tell the truth, I was surprised positively!
Are all decks shielded?
Are all decks shielded?