nation of the proposals submitted concerning additional low-power operations of the offset frequencies, will unduly delay a decision for their use for low-power, bio-medical telemetry purposes within hospitals, we are issuing a First Report and Order limited to this aspect of the proposal. The proceeding will remain open for future. consideration of other low-power uses that can be accommodated on these frequencies.

4. The in-hospital cardiac use contemplated in our Notice generally involves small telementry transmitters carried by ambulatory patients which transmit certain physiological data to a receiver-monitor. The comments agreed that this was a valid communications requirement which justifies frequency allocation. However, one of the issues raised in our Inquiry was whether these operations could reasonably co-exist with other co-channel and adjacent channel operations conducted in the vicinity of hospitals and which use higher transmitter powers.

5. The proposal to accommodate low-power, in-hospital telementry was predicated on our belief that the possibility of co-channel interference to the medical telemetry unit would be remote because of the shielding available within the hospital building. Adjacent channel interference was not believed to be a problem because of the combination of factors necessary to produce harmful interference. Our assumptions were contested by a number of parties. For example, API states, ". . . use of such telementry facilities on the upper floors of hospitals or medical centers could result in serious interference being received from nearby industrial systems, because the medical system receivers would be provided with visibility far exceeding that which was anticipated when Section 91.554 (c) was adopted Adjacent channel interference was also thought to be a problem. EIA states, "The channels which sandwich the 12.5 kHz spaced offset frequencies permit powers in the area of 100 watts, or 1,000 times that of the proposed bio-medical systems. . . ." and suggested that "the potential for dangerous and destructive interference [to in-hospital telemetry systems] is substantially greater on these frequencies than on those provided for this purpose in the Commission's March 8, 1972, Report and Order in Docket 19231 (VHF-TV sharing.)" 2

"2

6. In reply comments, Hewlett-Packard, the petitioner in this proceeding, did not contest the possibility of interference, but argues that it may be minimized through the use of selective modulation and filtering techniques and alarm circuitry. Further, it suggests, as a possibility for minimizing adjacent channel interference, limiting inhospital telemetry operations to the offset frequencies located within the band 460.650-460.875 MHz, since regularly assigned frequencies within this band are primarily available at air terminals for comparatively low-power operations.

7. ITT also considered adjacent channel interference and states:

1 Offset frequencies became available as a result of channel-splitting action in Docket 13847 (33 FR 3114).

2 Rules adopted in the proceeding in Docket No. 19231 permit low-power medical telemetry operation on selected VHF-TV channels under the provisions of Part 15 of our Rules. Alarm circuitry indicates an interference condition which might result in an inaccurate display of a patient's condition necessitating direct observation of the patient until the interference condition passes.

"The fixed telemetry receiver can be made highly stable and highly selective because there is no size or power consumption restriction. Also, the receiving antenna can be a radiating cable (otherwise known as leaky line) whose characteristics are: to have good pickup of signals close-in, but have attenuated response to far-field signals. All of the above technical factors are favorable to medical telemetry systems co-existing with adjacent channel (12.5 kHz away) business radio stations without mutual interference."

In addition, ITT notes medical telemetry transmitters are exposed to a very narrow temperature range (as it is carried next to a patient's body) resulting in greater transmitter stability than would be expected in transmitters used for voice operations in industrial complexes which are subject to temperatures ranging from -30°C to +50°C. Further, voice transmissions require greater bandwidth than bio-medical telemetry transmissions, necessitating the use of a receiver with less selectivity than could be employed for bio-medical telemetry reception.

8. ITT's and Hewlett-Packard's arguments are persuasive, and we tend to believe that the potential for co- and adjacent channel interference to well designed operations on offset frequencies may not be as significant as suggested by some of the other comments. However, we did not receive sufficient data to enable us to determine with reasonable assurance the precise conditions under which offset frequencies may be used without serious interference problems and; as we have said, we will pursue this issue further in this proceeding

9. Meanwhile, we agree with Hewlett-Packard that in-hospital, lowpower telemetry systems can be accommodated in the interim on the offset frequencies located between the frequencies allocated in the 460-470 MHz band for land mobile operations in air terminals. This would make available a total of 18 frequencies and would accommodate the reasonable requirements of many hospitals for the time being. As pointed out by Hewlett-Packard, in the 87 largest urban areas, the aviation terminal frequencies are used within known areas (the general confines of air terminals) with relatively low power, i.e., 20 watts for base stations and 3 watts for mobile stations. The requirement for multi-frequency systems is related to hospital size and facilities, and access to these frequencies by hospitals within these areas should be relatively interference free. Outside the 87 largest urban areas where the aviation terminal frequencies may be used for land mobile operations employing up to 180 watts power, the interference potential to 12.5 kHz offset frequencies in hospitals is considerably greater. In these areas, hospitals will need a small number of frequencies; and we expect this requirement can be accommodated on the 8 low-power business channels which are limited to 3 watts power and are not adjacent to frequencies on which higher powers are permitted. Accordingly, we believe that well-designed, in-hospital telemetry systems on the offset frequencies can be expected to operate there without significant adjacent interference problems. Specifically, therefore, we will amend our rules to permit one-way, non-voice bio-medical telemetry operations on the 18, 12.5 kHz offset frequencies located within the bands 460.650460.875 and 465.650-465.875 MHz in hospitals, medical, and convalescent centers. Further, to minimize co-channel interference possibilities, we are restricting for the time being all new operations on these offsets to bio-medical telemetry operations. Existing systems cur

rently utilizing these offset frequencies will continue to be authorized; but no new non-medical telemetry operations will be permitted.

10. In reaching our conclusion to permit limited in-hospital, biomedical telemetry on the 460-470 MHz offset frequencies, we considered, among other matters, the argument advanced by Spacelabs, Inc., to the effect that operation of the radio telemetry units near heart pacemakers could cause the pacemaker to function erratically and could harm the patient on which it (the pacemaker) is attached. The Commission appreciates Spacelab's concern. We note, however, Hewlett-Packard's reply comment that the:

"Susceptibility of a pacemaker to radio frequency radiation is not peculiar to the frequencies involved in this proceeding. Medical telemetry is only one of many sources of radio frequency radiation which may interfere with the proper operation of a pacemaker. Because medical telemetry units are operated in close proximity with pacemakers, it has become common clinical practice to evaluate the compatibility of a pacemaker and a medical telemetry unit under actual operating conditions on a patient before the patient is permitted to ambulate.”

11. The problem noted by Spacelabs is, as stated by HewlettPackard, not limited to the frequencies in the 450-470 MHz band. The U.S. Department of Health, Education, and Welfare, in a publication. entitled "Electro-magnetic Radiation Interference with Cardiac Pacemakers," has stated:

‘. . . pacemaker disfunction has been reported in the vicinity of the following: radio stations, motorcycles, and gasoline ignition systems, radar sites, and electric shaver, and a television receiver, as well as an electric mixer. This brief list is not intended to be all inclusive, but serves to point out the wide variety of potential interference sources presented daily to the pacemaker wearer. Physicians have been alerted to the potential interference from electronic products through the available literature; and they, in turn, have been able to advise their pacemaker patients on possible problems.” (Emphasis added)

Because awareness of the problem of interference to cardiac pacemakers is well publicized, the Commission believes the public interest can best be served by complying with Hewlett-Packard's request. It is our belief that this particular interference problem is best dealt with by the medical personnel concerned. Should trouble occur because of interference between the telemetry transmitter installed on a patient and his pacemaker, this effect should be immediately apparent at the monitor. Corrective action can then be taken.

12. Few other items require decision. We see no substantial difference between our proposal to permit 100 milliwatts "output" and 100 milliwatts "radiated" power urged by Hewlett-Packard. Therefore, we will adhere to our original proposal and permit a maximum of 100 milliwatts of output power for bio-medical telemetry units operating on the frequencies in question because it is easier to enforce the power limitation through our type-acceptance program.

13. ARINC suggested that it be allowed to coordinate the selection of the offset frequencies within the air terminal allocation. Since ARINC coordinates the regularly assignable air terminal frequencies, it would probably be logical to allow it to coordinate the offsets, also. However, the National Association of Business and Educational Radio, Inc., has been doing this for applicants using these as well as the other offsets in industrial complexes; and it would be more practical to continue the existing arrangements until the whole question relating to

the use of all of the offset frequencies in the 460-470 MHz band is settled in a subsequent phase of this proceeding.

14. Finally, as urged by Reach Electronics and Hewlett-Packard, we will not impose precise modulation restrictions beyond limiting the use to telemetry and to non-voice techniques.

15. In view of the foregoing, the Commission finds adoption of a rule amendment permitting bio-medical telemetry on the offset frequencies between the air-terminal frequencies in the bands 460.650460.875 MHz and 465.650-465.875 MHz will serve the public interest. The rule amendment set forth in the attached appendix will, therefore, permit such operations on the specified offsets. Because of the interest displayed by the Federal Government concerning the use of these frequencies for telemetry operations in government hospitals, we are also amending Part 2 of the Commission's Rules to permit this limited government use of these frequencies under the same technical parameters prescribed for nongovernment users.

16. Accordingly, Pursuant to authority contained in Section 4(i) and 303 of the Communications Act of 1934, as amended, IT IS ORDERED, That effective July 6, 1973, Parts 2 and 91 of the Commission's Rules ARE AMENDED, as shown in the attached Appendix. FEDERAL COMMUNICATIONS COMMISSION,

APPENDIX

BEN F. WAPLE, Secretary.

1. Part 2 of the Commission's Rules is amended as follows:

Section 2.106 is amended by the addition of U.S. footnote 209 to read as follows:

US209 The use of frequencies 460.6625, 460.6875, 460.7125, 460.7375, 460.7625, 460.7875, 460.8125, 460.8375, 460.8625, MHz and 465.6625, 465.6875, 465.7125, 465.7375, 465.7625, 465.7875, 465.8125, 465.8375, 465.8625. MHz may be authorized with 100 milliwatts or less output power to Government and non-Government radio stations for one-way, non-voice bio-medical telemetry operations in hospitals, or in medical or convalescent

centers.

2. Section 91.554 (c) is amended, and a new paragraph (d) is added to read as follows:

§ 91.554 Frequencies available.

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(c) Except for frequencies separated by 12.5 kHz from regularly assigned frequencies in the bands 460.650-460.875 MHz and 465.650-465.875 MHz, lowpower mobile stations of 3 watts or less may be assigned any frequency separated by 12.5 kHz from any mobile frequency in the band 450-470 MHz listed in

paragraph (a) of this section. Such station may be used to provide any function of a base, mobile relay, or mobile station; Provided, That all operation is limited to the confines of an industrial complex. When used as a base station or mobile relay, the height of the antenna shall not exceed 20 feet above ground. All operation is subject to the condition that harmful interference is not caused to adjacent mobile operations.

(d) Low-power mobile stations of 100 mw or less output power may be assigned any frequency separated by 12.5 kHz from a regularly assigned frequency in the bands 460.650-460.875 MHz and 465.650-465.875 MHz listed in paragraph (a) of this section, for one-way, non-voice bio-medical telemetry operations in hospitals, or in medical or convalescent centers.

41 F.C.C. 2d

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