Using OpcCmd Utility as OPC DA Client
From OPC Labs Knowledge Base
OpcCmd -i daClient subscribeItem OPCLabs.KitServer.2 Demo.Ramp 200
Using OPC NET API:
OpcCmd -i daclient --!property ClientSharedParameters.EnableNativeClient=[Boolean]false subscribeItem OPCLabs.KitServer.2 Demo.Ramp 200