Sec.  90.537   Trunking requirement.

   (a) General use channels. All systems using six or more narrowband channels
   in the 764–776 MHz and 794–806 MHz frequency bands must be trunked systems,
   except for those described in paragraph (b) of this section.

   (b) Interoperability channels. Trunking is permitted only on
   Interoperability channels specified in  Sec. 90.531(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.

   [ 66 FR 10636 , Feb. 16, 2001]