Digital TV could hinder telemetry equipment
July 1, 1998
Digital TV could hinder telemetry equipment
Federal agencies issue warning
The advent of digital television could have severe consequences for your unit's telemetry equipment, two federal agencies warn.
The Food and Drug Administration (FDA) and the Federal Communications Commission (FCC) both caution that telemetry systems that use television frequencies may suffer interference from digital television (DTV) transmissions.
Such incidents could involve any telemetry devices, including cardiac monitors, the agencies said in a jointly issued alert. For example, the FDA said the telemetry system of a Dallas hospital was "rendered unusable" when a local TV station began broadcasting over a channel previously used only by the hospital. A second hospital in the city also was affected. No patient deaths occurred, the announcement said.
DTV encroaching on channels 7-13
The problem is that many medical devices that employ television frequencies operate in the channel 7-13 spectrum. Traditionally, TV stations have not used those bands, leaving them open for medical devices. However, the advent of DTV means more stations are gaining licenses to operate from that same spectrum. Under FCC rules, secondary users of a frequency, such as hospitals and nursing homes, are not allowed to interfere with the signals of primary users - TV stations - but TV station signals can interfere with the signals of secondary users.
The problem will get worse in the future. In the next six months, 10 major digital television markets will begin transmitting signals on previously unused channels. Most of these first DTV stations will operate outside the channel 7-13 band, but some will broadcast within that band. Many more DTV stations will be on line by 2003 and could begin transmitting at any time, the agencies warned.
Find out who may be taking your channels
The latest information on which channels have been allocated to TV stations is listed by geographic location in an FCC table of allotments. This table can be found on the FCC Web site by going to: www.fcc.gov/Bureaus/Engineering_Technology/News_Releases/1998/nret8002.html. (Note that the address is uppercase and lowercase sensitive.) Next, select the DTV Table of Allotments. (View in either WordPerfect version or Acrobat version to see table headings.)
The FDA recommends hospitals work with the manufacturers of their telemetry systems to determine the channel/frequencies your equipment use and to consult the FCC table of allotments for DTV channels that will be coming on-line in your area.
If your telemetry systems use channels that are scheduled to be used by a local station you should work with the manufacturer to:
· consult with the local television stations to determine when they plan to begin broadcasting on those channels;
· change your telemetry channels to unused channels before the stations begin using them.
"If you find that your telemetry systems are transmitting on channels that will remain unused, you should not have a problem due to DTV transmissions," the FDA said.
The FCC also said that it will ensure that TV stations communicate with local health care facilities to avoid problems and that it also will contact the makers of medical telemetry devices about the problem.
The FDA also noted that telemetry equipment falls under the Safe Medical Devices Act of 1990, which requires hospitals to report deaths and serious illnesses and injuries connected to the use of devices. Frequency interference falls under this category. If a telemetry system fails, that should be reported directly to MedWatch, the FDA's voluntary reporting program.
Submit reports to: MedWatch, Food and Drug Administration, HF-2, 5600 Fishers Lane, Rockville, MD 20857. Telephone: (800) FDA-1088. Fax: (800) FDA-0178.
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