---
kind: "section"
citation: "47 C.F.R. § 90.235"
title: "47"
number: "90.235"
heading: "Secondary fixed signaling operations."
url: "https://uscodex.org/cfr/47/90.235"
---

# §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) 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) [Reserved]
- (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 §§ [90.137(b)](/cfr/47/90.137.md?p=b), [90.425](/cfr/47/90.425.md), and [90.429](/cfr/47/90.429.md).
- (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 §§ [90.317(a)](/cfr/47/90.317.md?p=a), [90.557](/cfr/47/90.557.md) and [90.637](/cfr/47/90.637.md) are exempt from the foregoing provisions of this section.

## Notes

### Amendments

[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; 72 FR 35195, June 27, 2007; 72 FR 44424, Aug. 8, 2007; 79 FR 39339, July 10, 2014; 90 FR 57710, Dec. 12, 2025]

### Authority

Authority: 47 U.S.C. 154(i), 161, 303(g), 303(r), 332(c)(7), 1401-1473

### Source

Source: 43 FR 54791, Nov. 22, 1978, unless otherwise noted.

### Amendments

[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; 72 FR 35195, June 27, 2007; 72 FR 44424, Aug. 8, 2007; 79 FR 39339, July 10, 2014; 90 FR 57710, Dec. 12, 2025]