Sec. 90.235  Secondary fixed signaling operations.

    Fixed operations may, subject to the following conditions, be 
authorized on a secondary basis for voice, tone or impulse signaling on 
a licensee's mobile service frequency(ies) above 25 MHz within the area 
normally covered by the licensee's mobile system. Voice signaling will 
be permitted only in the Public Safety Pool.
    (a) The bandwidth shall not exceed that authorized to the licensee 
for the primary operations on the frequency concerned.
    (b) The output power shall not exceed 30 watts at the remote site.
    (c) A1D, A2D, F1D, F2D, G1D and G2D emissions may be authorized. In 
the Police Radio Service, A3E, F1E, F2E, F3E, G1E, G2E, or G3E emissions 
may also be authorized.
    (d) Except for those systems covered under paragraph (e) of this 
section, the maximum duration of any non-voice signaling transmission 
shall not exceed 2 seconds and shall not be repeated more than 3 times. 
Signaling transmissions may be staggered at any interval or may be 
continuous. In the Public Safety Pool, the maximum duration of any voice 
signaling transmission shall not exceed 6 seconds and shall not be 
repeated more than 3 times.
    (e) Until December 31, 1999, for systems in the Public Safety Pool 
authorized prior to June 20, 1975, and Power and Petroleum licensees as 
defined in Sec. 90.7 authorized prior to June 1, 1976, the maximum 
duration of any signaling transmission shall not exceed 6 seconds and 
shall not be repeated more than 5 times. For Power licensees authorized 
between June 1, 1976, and August 14, 1989, signaling duration shall not 
exceed 2 seconds and shall not be repeated more than 5 times. Such 
systems include existing facilities and additional facilities which may 
be authorized as a clear and direct expansion of existing facilities. 
After December

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31, 1999, all signaling systems shall be required to comply with the two 
second message duration and three message repetition requirements.
    (f) Systems employing automatic interrogation shall be limited to 
non-voice techniques and shall not be activated for this purpose more 
than 10 seconds out of any 60 second period. This 10 second timeframe 
includes both transmit and response times.
    (g) Automatic means shall be provided to deactivate the transmitter 
in the event the r.f. carrier remains on for a period in excess of 3 
minutes or if a transmission for the same signaling function is repeated 
consecutively more than five times.
    (h) Fixed stations authorized pursuant to the provisions of this 
section are exempt from the requirements of Secs. 90.137(b), 90.425, and 
90.429.
    (i) Base, mobile, or mobile relay stations may transmit secondary 
signaling transmissions to receivers at fixed locations subject to the 
conditions set forth in this section.
    (j) Under the provisions of this section, a mobile service frequency 
may not be used exclusively for secondary signaling.
    (k) The use of secondary signaling will not be considered in whole 
or in part as a justification for authorizing additional frequencies in 
a licensee's land mobile radio system.
    (l) Secondary fixed signaling operations conducted in accordance 
with the provisions of Secs. 90.317(a), or 90.637(c), or 90.731 are 
exempt from the foregoing provisions of this section.
[ 54 FR 28679 , July 7, 1989, as amended at  57 FR 34693 , Aug. 6, 1992;  58 FR 30996 , May 28, 1993;  60 FR 50123 , Sept. 28, 1995;  62 FR 18927 , Apr. 
17, 1997]

    Effective Date Note: At  62 FR 18927 , Apr. 17, 1997, Sec. 90.235 was 
amended by revising the last sentence of the introductory text, the last 
sentence of paragraph (d), and paragraph (e), effective Oct. 17, 1997.