Responsible party. The party or parties responsible for the compliance of terminal equipment or protective circuitry intended for connection directly to the public switched telephone network with the applicable rules and regulations in this part and with the technical criteria published by the Administrative Council for Terminal Attachments. If a Telecommunications Certification Body certifies the terminal equipment, the responsible party is the holder of the certificate for that equipment. If the terminal equipment is the subject of a Supplier's Declaration of Conformity, the responsible party shall be: the manufacturer of the terminal equipment, or the manufacturer of protective circuitry that is marketed for use with terminal equipment that is not to be connected directly to the network, or if the equipment is imported, the importer, or if the terminal equipment is assembled from individual component parts, the assembler. If the equipment is modified by any party not working under the authority of the responsible party, the party performing the modifications, if located within the U.S., or the importer, if the equipment is imported subsequent to the modifications, becomes the new responsible party. Retailers or original equipment manufacturers may enter into an agreement with the assembler or importer to assume the responsibilities to ensure compliance of the terminal equipment and to become the responsible party.