Disclosed herein are compounds of formula wherein L1, L2, L3, R1, R4, R5, and R6 are as defined in the specification. A coupler is in fluid communication with the associated fluid inlet. The ingress and egress elements preferably support Ethernet or other protocol providing connectionless media with a stateful connection. The non-volatile storage elements with the intermediate VTH distribution are programmed to third and fourth VTH distributions. The anchoring system comprises a rigid plate comprising retainer suitable for retaining the anchor rod by abutment contact when the coupling member of the child seat exerts forces on the said anchor rod.