Goto Section: 90.423 | 90.427 | Table of Contents
Revised as of September 1, 2021
Goto Year:2020 |
§ 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 paragraphs (d)
and (e) 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
(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 Wireless Telecommunications Bureau 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
(iii) In the Industrial/Business Pool, railroad licensees (as defined
in § 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 is 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
(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 Â±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 Â±800 Hz. A licensee may be required to change the
frequency in order to prevent interference to the operations of another
(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
(c) Special provisions for identification in the Radiolocation Service.
(1) Stations in the Radiolocation Service are not required to identify
except upon special instructions from the Commission or as required by
paragraphs (c)(2) and (3) 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.
(3) Oceanographic radars operating in the bands shown in section
90.103(b) shall transmit a station identification (call sign) on the
assigned frequency, in international Morse code at a transmission rate
in accordance with paragraph (b)(2) of this section at the end of each
data acquisition cycle, but at an interval of no more than 20 minutes.
(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
(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 § 90.20(a)(2)(v).
(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
(9) It is a wireless microphone station operating in accordance with
the provisions of § 90.265(b).
(10) It is a Roadside Unit in a DSRCS system.
(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 or MTA or EA-based SMR licensees. All other
CMRS stations will be required to comply with the station
identification requirements of this paragraph.
(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. A licensee that identifies its call sign in this
manner must provide the Commission, upon request, information
sufficient to decode the digital transmission and ascertain the call
(f) Special provisions for stations licensed under this part that are
not classified as CMRS providers under part 20 of this chapter.
(1) 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.
(2) Stations licensed on an exclusive basis in the bands between 150
and 512 MHz that normally employ digital signals for the transmission
of data, text, control codes, or digitized voice may be identified by
digital transmission of the call sign. A licensee that identifies its
call sign in this manner must provide the Commission, upon request,
information sufficient to decode the digital transmission and ascertain
the call sign transmitted.
[ 43 FR 54791 , Nov. 22, 1978]
Editorial Note: For Federal Register citations affecting § 90.425, see
the List of CFR Sections Affected, which appears in the Finding Aids
section of the printed volume and at www.govinfo.gov.
Goto Section: 90.423 | 90.427
Goto Year: 2020 |
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