Sec.  90.673   Obligation to abate unacceptable interference.

   (a) Strict Responsibility. Any licensee who, knowingly or unknowingly,
   directly or indirectly, causes or contributes to causing unacceptable
   interference to a non-cellular licensee in the 800 MHz band, as defined in
   this chapter, shall be strictly accountable to abate the interference, with
   full cooperation and utmost diligence, in the shortest time practicable.
   Interfering licensees shall consider all feasible interference abatement
   measures, including, but not limited to, the remedies specified in the
   interference resolution procedures set forth in this chapter. This strict
   responsibility obligation applies to all forms of interference, including
   out-of-band emissions and intermodulation.

   (b) Joint and Several Responsibility. If two or more licensees knowingly or
   unknowingly, directly or indirectly, cause or contribute to causing
   unacceptable interference to a non-cellular licensee in the 800 MHz band, as
   defined in this chapter, such licensees shall be jointly and severally
   responsible for abating interference, with full cooperation and utmost
   diligence, in the shortest practicable time. This joint and several
   responsibility rule requires interfering licensees to consider all feasible
   interference abatement measures, including, but not limited to, the remedies
   specified in the interference resolution procedures set forth in this
   chapter. This joint and several responsibility rule applies to all forms of
   interference, including out-of-band emissions and intermodulation.

   (1) This joint and several responsibility rule requires interfering
   licensees to consider all feasible interference abatement measures,
   including, but not limited to, the remedies specified in the interference
   resolution procedures set forth in  Sec. 90.674(c). This joint and several
   responsibility rule applies to all forms of interference, including
   out-of-band emissions and intermodulation.

   (2) Any licensee that can show that its signal does not directly or
   indirectly, cause or contribute to causing unacceptable interference to a
   non-cellular licensee in the 800 MHz band, as defined in this chapter, shall
   not be held responsible for resolving unacceptable interference.
   Notwithstanding, any licensee that receives an interference complaint from a
   public safety/CII licensee shall respond to such complaint consistent with
   the interference resolution procedures set forth in this chapter.