This read-only DisplayString, up to 255 characters, gives an ASCII text description of why the last call to this peer terminated, intended as a fallback for when a management station cannot decode the raw ctDAWanDeviceLastDisconnectCause value, and updated on every call start or clear. An admin reads this human-readable text directly rather than needing to look up numeric cause codes for the interface type in use. For example, this field might simply read 'Remote end busy' for a peer entry, sparing the admin from decoding the corresponding ISDN cause code.