Who's asking: My sister Peggy
Most hospitals ban cell phones for the same reason that airplanes ban cell phones: the possibility that signals from the cell phones might cause radio frequency interference (RFI) with the hospital's internal communications and electronic systems. A study conducted in 2001, for example, found that holding a cell phone close to a pacemaker disrupted the pacemaker's function.
As with airplanes, improvements in wireless technology have lowered these risks. It's probably safe to use a cell phone in most hospitals nowadays -- but why take a chance?
If a cell phone does interfere with a building or an aircraft's telemetry, it does so whether or not you're talking on it. What matters is whether or not the phone is switched on. Cell phones in standby mode are still transmitting and receiving signals. When the sign says, "CELL PHONE USE PROHIBITED," turn it off, don't just switch it to vibrate. Take my word for it: you're not that important.
Dad might be getting out of Maine General this afternoon -- hurray! -- and then he can use his cell phone as much as he likes.
And a very happy birthday today to Frau Susanne Schulz, recently returned from her jet-set vacation. We miss you here in Maine, Sue.