---
kind: "section"
citation: "47 C.F.R. § 90.537"
title: "47"
number: "90.537"
heading: "Trunking requirement."
url: "https://uscodex.org/cfr/47/90.537"
---

# §90.537. Trunking requirement.

- (a) **General use and State License channels.** All fixed transmitter sites using six or more narrowband channels in the 769-775 MHz and 799-805 MHz frequency bands must be trunked, except for those described in [paragraph (b)](#b) of this section. This paragraph does not apply to Vehicular Repeater Systems (MO3) authorized on the General Use and State License channels listed in [§ 90.531(b)](/cfr/47/90.531.md?p=b).
- (b) **Interoperability and low power channels.** Trunking is permitted only on Interoperability channels specified in [§ 90.531(b)(1)(iii)](/cfr/47/90.531.md?p=b-1-iii). Trunked use must be strictly on a secondary, non-interference basis to conventional operations. The licensee must monitor and immediately release these channels when they are needed for interoperability purposes. All systems using narrowband low power channels listed in § [90.531(b)(3)](/cfr/47/90.531.md?p=b-3) and [(4)](/cfr/47/90.531.md?p=b-4) are exempt from the trunking requirements described in [paragraph (a)](#a) of this section.

## Notes

### Amendments

[79 FR 39340, July 10, 2014, as amended at 83 FR 30367, June 28, 2018]

### Source

Source: 63 FR 58651, Nov. 2, 1998, unless otherwise noted.

### 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

[79 FR 39340, July 10, 2014, as amended at 83 FR 30367, June 28, 2018]