By Aidan Malley

Published: 06:35 PM EST

Apple has already aired another commercial as part of its iPhone advertising blitz. Also, one waiter claims to have had some early unofficial experience with the device. And a US patent may show the way towards trouble-free calls.

4th iPhone spot airs on TV

On the heels of its first three ads, Apple has begun circulating a new ad on TV networks.

The 30-second ad, first noticed on CNBC, follows in step with the previous ads but shifts its attention to Safari's ability to display websites as their creators intended -- the "real" Internet, the ad says.

The ad is not yet available at Apple.com but can be seen via a YouTube capture at the end of this report.

Restaurant server gains iPhone practice?

Meanwhile, one employee of a high-class Manhattan restaurant may have been one of the first outside of a small circle of owners to try the iPhone for himself.

Posting in Ars Technica's Mac forum, "Felix K" says a customer dining at Balthazar lent his rare cellphone to the waiter for a few minutes of direct contact. The experience was "amazing," he says, proving the interface to be quick and stable. The screen was allegedly free of streaks and the mystery client easily typed out text when the phone was returned.

Even the packaging, which had accompanied the phone's owner to the New York City eatery, is reportedly an "elegant" black cube, giving the employee an almost uniformly positive impression of the device despite the inability to test calling, EDGE Internet access, or e-mail.

"It feels like an Apple product. Consider it another Mac," Felix adds. "That made me pretty eager to get it. "

Patent guards against dropped iPhone calls

Apple has also been granted a recent US patent for a device that could eliminate potential signal drop-outs and other interference that could interrupt phone calls and other essential wireless traffic.

Described as an "accessory detector," the module would be embedded in a "wireless mobile device" such as a cellphone and tie into both black and white lists on the parent device to warn the user when nearby devices might interrupt the normal wireless signal. Borderline acceptable peripherals could force the handheld to adjust its antennas or its frequency tuning, the patent explains.

It's unclear at this time whether the patent, filed in late December of last year, might apply to the first-genertion iPhone or might be considered for a future model.