Sec.  80.106   Intercommunication in the mobile service.

   (a) Each public coast station must exchange radio communications with any
   ship or aircraft station at sea; and each station on shipboard or aircraft
   at  sea  must  exchange radio communications with any other station on
   shipboard or aircraft at sea or with any public coast station.

   (b)  Each  public  coast  station  must  acknowledge  and  receive all
   communications  from  mobile  stations  directed  to  it, transmit all
   communications delivered to it which are directed to mobile stations within
   range  in  accordance with their tariffs. Discrimination in service is
   prohibited.