WHITE PAPER
Digivance
®
ICS
For Healthcare Applications
Digivance
®
ICS
For Healthcare Applications
Wireless in Hospitals – Good or Bad?
As you enter most hospitals, it is very likely that you will be greeted with a sign
looking something like this:
Studies have shown that radiation from cell phones has the potential to interfere
with cardiopulmonary monitoring devices, and in some cases may even cause
malfunction of patient ventilators
1
. Such evidence would seem to indicate that
cell phones constitute a significant risk to patient health and safety, warranting
their ban from hospital facilities. But many of the same hospitals that are
banning cell phones are, at the same time, bringing more and more wireless
equipment into the hospital environment. Wireless Local Area Networks (LANs)
are being installed at a rapid rate. The mobile access to medical records provided
by wireless LANs is being touted for its benefits to patients, in articles with titles
such as: “Wireless LANs: Just What the Doctor Ordered”
2
and “Wireless Is the
Healthy Choice”
3
. In addition to network access at the nurse’s station, such
wireless systems often include mobile voice handset coverage throughout
the building

reduce their power in good coverage areas, most studies
on the effects of cell phone interference assume that
within hospital buildings, the cell phone will generally
be operating at its maximum rated power.
At the maximum cell phone power of 600 mW,
the Mayo study found that “clinically important”
interference occurred 7.4% of the time if the phone
was within 60 inches of a piece of medical electronics.
Actual equipment failure occurred only with one piece
of tested equipment, and this occurred only when
the 600 mW cell phone was placed within 5-10 cm
of a data port on the rear panel of the device
5
. While
this may seem like a minimal threat, the healthcare
environment mandates erring on the side of safety;
hence, the ban on cell phones.
At 20 mW, however, the radius of potential interference
is reduced from 60 inches to about 11 inches; and the
risk of an equipment failure, such as the one noted in
this study, becomes almost non-existent. This reduces
the risk significantly enough for such low power wireless
systems to be considered “hospital safe”.
Problems with Cell Phone Bans
There are several difficulties with the widely adopted
ban on the use of cell phones in hospitals. One big
disadvantage of this policy is that it deprives medical
workers, as well as patients and their families, of a
primary means of communication–in fact the very
means of communication that may not only be

phones, one for use inside and one for outside the
building. Such local systems can be expensive and
difficult to integrate with the existing PBX. Handsets,
in particular, tend to be more expensive, as they do
not benefit from the quantity distribution and service
provider subsidies that keep cell phone prices low.
In addition, a local wireless phone system provides
access for hospital personnel only, not for hospital
visitors. It also does nothing to solve the problem of
energy being transmitted continually by idle (but still
turned on) phones in pockets and purses.
The Digivance
™
Solution
The Digivance
™
Indoor Coverage Solution (ICS)
enables employees and visitors to use their cell phones
within hospital buildings while minimizing the risk
of interference to medical equipment. It does this by
distributing cell phone coverage throughout the building
through a series of low power Digital Remote Units
(DRUs), each transmitting a maximum of +13 dBm
(20 mW) of power.
Placing low power DRUs throughout the building means
that cell phones will only have to transmit as far as an
antenna which is, at most, a few hundred feet rather
than miles away. In addition, its signals do not need to
penetrate through the steel outer frame of the building.
This means that cell phones used within the building

can be used to independently control the amount
of power reduction in different sections of the
building. Sparsely placed antennas will result in
a wider range of handset powers, which may
be acceptable in public areas of the building;
more closely spaced antennas will provide tighter
power control in particularly sensitive areas, such
as critical care units.
The Digivance Advantage
Digivance ICS uses advanced technology that
sets it apart from all other indoor coverage
systems. It is the only such system that
distributes its wireless coverage over digital
fiber. Fiber, unlike coax or twisted pair wiring, is
completely immune to reception or generation
of electromagnetic interference, making it easy
to install alongside other wiring without fear
of noise or crosstalk. Digital optics means that
either single or multimode fiber can be used
without degrading signal quality, allowing the
installer to take advantage of any unused fiber
that may already be in place within the building.
Digital fiber also minimizes the noise level on
the path back to the base station. Keeping
the noise level on this path low is essential to
minimizing cell phone output power, and only
the digital optics of the Digivance system can
offer the lowest possible noise level, regardless
of the length of fiber. Digital optics also enables
complete flexibility of installation topology and

from optical path loss. Every antenna in the
system, from the closest to the farthest, will
provide the same high quality signal–enabling
uniform coverage throughout the largest
buildings or even multi-building campuses.
In short, the need for safe, high quality, and
trouble-free wireless communications in the
hospital environment has been met with ADC’s
unique indoor coverage solution–the digital
advantage of Digivance.
This hospital is equipped with
Digivance
™
coverage. Feel free to use
your cell phones in this facility.