gateway table
  ID
  gateway_id
  description
  npa
  contact_name
  contact_phone
  username
  password
  credit
  active 

intlrates
   ID
   location
   countrycode
   prefix
   rate

intlroutes
   ID
   countrycode
   prefix
   carrierid
   rate

carrier
   carrierid
   carrier_name
   dialstring