Sec. 90.425  Station identification.

    Stations licensed under this part shall transmit identification in 
accordance with the following provisions:
    (a) Identification procedure. Except as provided for in paragraph 
(d) of this section, each station or system shall be identified by the 
transmission of the assigned call sign during each transmission or 
exchange of transmissions, or once each 15 minutes (30 minutes in the 
Public Safety Pool) during periods of continuous operation. The call 
sign shall be transmitted by voice in the English language or by 
International Morse Code in accordance with paragraph (b) of this 
section. If the station is employing either analog or digital voice 
scrambling, or non-voice emission, transmission of the required 
identification shall be in the unscrambled mode using A3E, F3E or G3E 
emission, or International Morse, with all encoding disabled. 
Permissible alternative identification procedures are as follows:
    (1) A mobile relay stations call sign may be used to identify the 
associated control and mobile stations, except in the Public Safety Pool 
where the stations operate on frequencies below 450 MHz. Alternatively, 
a base station (including a mobile relay station) which is controlled by 
radio may be identified by the transmission of the call sign of the 
station at which communications originate.
    (2) One or more fixed relay stations may be identified by the 
transmission of the call signs of the stations at which the 
communications originate.
    (3) When a mobile station transmits on a different frequency than 
its associated base station, the assigned call sign of either the mobile 
station or the base station may be transmitted. Further, a single mobile 
unit in the licensee's authorized geographic area of operation may 
transmit station identification on behalf of any other operating mobile 
units in the fleet.
    (4) Use of an identifier other than the assigned call sign. (i) In 
the Public Safety Pool, mobile units licensed to a governmental entity 
and which operate on frequencies above 30 MHz may use an identifier 
which contains, at a minimum, the name of the licensee if the licensee 
maintains at the station a list of the special identifiers to be used by 
the mobile units.
    (ii) In the Industrial/Business Pool, licensees may request the 
Commission's local Engineer-in-Charge to approve the use of special 
mobile unit identifiers in lieu of the assigned call sign. Such 
requests, however, will not be granted where it appears that harmful 
interference to international operations may be caused by stations below 
50 MHz, or by stations operating in areas within 80 km (50 miles) of an 
international boundary, or where it appears that the proposed method of 
identification will not adequately distinguish the mobile units of the 
applicant from the mobile units of other licensees in the area.

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    (iii) In the Industrial/Business Pool, railroad licensees (as 
defined in Sec. 90.7) may identify stations by the name of the railroad 
and the train number, caboose number, engine number, or the name of the 
fixed wayside station. If none of these forms are practicable, any 
similar name or number may be designated by the railroad concerned for 
use by its employees in the identification of fixed points or mobile 
units; Provided, That, a list of such identifiers is maintained by the 
railroad. An abbreviated name or the initials of the railroad may be 
used where such are in general usage. In those areas where it is shown 
that no difficulty would be encountered in identifying the transmission 
of a particular station (as, for example, where stations of one licensee 
are located in a yard isolated from other radio installations), approval 
may be given to a request from the licensee for permission to omit the 
station identification.
    (5) Use of identifiers in addition to assigned call signs. Nothing 
in this section shall be construed as prohibiting the transmission of 
station or unit identifiers which may be necessary or desirable for 
system operation, Provided, That, they are transmitted in addition to 
the assigned station call sign or other permissible form of 
identification.
    (b) Use of automatic Morse code identification equipment. 
Automatically activated equipment may be used to transmit station 
identification in International Morse Code pursuant to the following 
conditions:
    (1) The signal output of the automatic identification equipment 
shall be connected to the transmitter at the microphone input or any 
other manufacturer-provided signal input terminal and shall be adjusted 
to produce 40 percent plus-minus 10 percent of the maximum 
permissible modulation or deviation level. This adjustment shall be 
performed when all other modulating signals are absent.
    (2) The Morse code transmission rate shall be maintained between 20 
and 25 words per minute.
    (3) The frequency of the keyed tone comprising the identification 
signal shall be 1200 plus-minus 800 Hz. A licensee may be 
required to change the frequency in order to prevent interference to the 
operations of another co-channel licensee.
    (4) Should activation of automatic Morse code identification 
equipment interrupt the communications of another co-channel licensee, 
the Commission may require the use of equipment which will delay 
automatic station identification until such co-channel communications 
are completed.
    (c) Special provisions for identification in the Radiolocation 
Service. (1) Stations in the Radiolocation Service are not required to 
identify except upon specific instruction from the Commission or as 
required by paragraph (c)(2) of this section.
    (2) Stations in the Radiolocation Service operating on frequencies 
above 3400 kHz that employ spread spectrum techniques shall transmit a 
two-letter manufacturer's designator, authorized by the Commission on 
the station authorization, at the beginning and ending of each 
transmission and once every 15 minutes during periods of continuing 
operation. The designator shall be transmitted in International Morse 
Code at a speed not exceeding 25 words per minute, and the spread 
spectrum mode of operation shall be maintained while the designator is 
being transmitted. The identifying signal shall be clearly receivable in 
the demodulated audio of a narrow-band FM receiver.
    (d) General exemptions. A station need not transmit identification 
if:
    (1) It is a mobile station operating on the transmitting frequency 
of the associated base station.
    (2) It is a mobile station in the Public Safety Pool using F1E or 
G1E emission.
    (3) It is transmitting for telemetering purposes or for the 
activation of devices which are employed solely as a means of attracting 
attention, or for remote control purposes, or which is retransmitting by 
self-actuating means, a radio signal received from another radio station 
or stations.
    (4) It is any type of radiopositioning or radar station authorized 
in a service other than the Radiolocation Service.
    (5) It is used solely for automatic vehicle monitoring or location.
    (6) It is a paging station authorized in accordance with the 
provisions of Sec. 90.20(a)(2)(v).

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    (7) It is a mobile station employing non-voice emissions and the 
associated base station identifies on behalf of the mobile unit(s).
    (8) It is a base or mobile station in the 220-222 MHz band 
authorized to operate on a nationwide basis in accordance with subpart T 
of this part.
    (9) It is a wireless microphone station operating in accordance with 
the provisions of Sec. 90.265(b).
    (e) Special provisions for stations licensed under this part that 
are classified as CMRS providers under part 20 of this chapter.
    (1) Station identification will not be required for 929-930 MHz 
nationwide paging licensees and MTA-based SMR licensees. All other CMRS 
stations will be required to comply with the station identification 
requirements of paragraphs (a) through (d) of this section.
    (2) CMRS stations subject to a station identification requirement 
will be permitted to use a single call sign for commonly owned 
facilities that are operated as part of a single system. The call sign 
must be transmitted each hour within five minutes of the hour, or upon 
completion of the first transmission after the hour.
    (3) CMRS stations granted exclusive channels may transmit their call 
signs digitally. The station licensee must provide the Commission with 
information sufficient to decode the digital transmission to ascertain 
the transmitted call sign.
[ 43 FR 54791 , Nov. 22, 1978]

    Editorial Note:  For Federal Register citations affecting 
Sec. 90.425, see the List of CFR Sections Affected in the Finding Aids 
section of this volume.

    Effective Date Note: At  62 FR 18934 , Apr. 17, 1997, Sec. 90.425 was 
amended by revising the first sentence of the introductory text of 
paragraph (a), the first sentences of paragraphs (a)(1), (a)(4)(ii), and 
(a)(4)(iii), and paragraphs (a)(4)(i), (d)(2), and (d)(6), effective 
Oct. 17, 1997.