This read-only AtmAddress reports the Called Party Subaddress of the call, an additional addressing field identifying a specific sub-endpoint at the destination. An administrator uses this when the called address alone does not pinpoint which sub-endpoint at the destination the call is intended for. For example, a PBX gateway sharing one called address across many extensions relies on cwspCallCalledSubAddr to route the incoming call to the correct extension, and an operator reads this object to confirm that routing.