default namespace = ""
namespace xsi = "http://www.w3.org/2001/XMLSchema-instance"

start =
  element param1-param2-info {
    attribute xsi:noNamespaceSchemaLocation { xsd:anyURI },
    element register {
      element service { xsd:integer } &
      element subservice { xsd:integer } &
      element apid { xsd:integer }? &
      (element param1-offset { xsd:integer } &
      element param1-width { xsd:integer })? &
      (element param2-offset { xsd:integer }&
       element param2-width { xsd:integer })?
    }+
  }