This read-only INTEGER reports the type of the ATM device as either public(1) or private(2), reflecting which UNI signaling variant governs this interface. An administrator checks this to confirm whether the interface is operating as a public or private UNI, which affects which signaling parameters and address formats are expected. For example, an interface expected to connect to a carrier's public ATM network but reporting private(2) alerts an operator to a UNI-type mismatch worth investigating.