Infinity Surveillance Technology

I don’t know if this is the right place for this, but I have question about Infinity technology:

Can anyone verify this claim?

Computer hacker technology can now secretly turn ON your
Cell Phone and allow any interested Eavesdropper to actually
overhear every conversation held in the vicinity of your Cell Phone
. . . without you ever knowing that it had been turned ON!

No longer is it necessary for an Eavesdropper to "plant" any
specialized surveillance equipment in order to Listen-In on
your confidential conversations.

If you're like most of us, your Cell Phone is rarely more than
6 feet away from you. It's become a constant and trusted
companion.

But, today's ever-ingenious Eavesdropper can now secretly
turn on the microphone of your Cell Phone and actually
overhear everything that occurs within 15 feet of your phone
while it sits "innocently" at your side.

www.counter-surveillance.com...

That excerpt is from an advertisement for a 200 dollar bug detector, so I don't know if I should believe them or if they just want to make you paranoid so you buy their stuff. I read something else that suggested a transmitter needed to be implanted in the phone, but the guy was talking about when he used one in the 70s.

The advertisers say someone can call your cell phone with one and turn it into an active transmitter. Does anyone know that claim to be a fact?