It is well-established that technological standards are subject to network externalities. These lead to lock-in situations with asymmetric (oligopolistic or monopolistic) industry structure and occasionally to persisting shortcomings in the current industry standard despite technically feasible alternatives. Taking the ICT sector as an example this paper discusses the special case of inter-sectoral tying of standards, interconnected network effects of connected standards in different sectors, and the resulting impact on the industry structure. Qualitative and quantitative evidences suggest that this phenomenon is very common in the ICT sector, possibly also in other sectors. The problem is formally analyzed as a replicator model and as an agent-based simulation model. It is found that tying reinforces lock-ins and the resulting effects.