Vendors may choose one of two levels of certification for their products:
Self-Certified – Tests are conducted by the vendor themselves using their own test equipment. Tests do not involve any third party.
Verified – Tests are carried out against existing WITS Verified devices in conjunction with the vendors of those WITS Verified devices. This ensures a greater level of confidence that the equipment complies with the protocol and delivers interoperability.
Note that in both cases the WITSPSA does not check or approve the claimed certification. The only checks made are that the correct documents have been submitted and that they are in the correct format and consistent with one another (see further details below). It is incumbent upon prospective buyers to ensure that the equipment fulfils their specific requirements. It is recommended that new products wishing to claim WITS-DNP3 compliance complete full verified status testing as this provides a greater level of confidence than self-certified for prospective purchasers that interoperability has been proven.