When a mixed-mode simulator is used, some method must be provided for translating data between the different simulation algorithms. XSPICE's Code Model support allows you to develop models that work under the analog simulation algorithm, the event-driven simulation algorithm, or both at once.

In XSPICE, models developed for the express purpose of translating between the different algorithms or between different User-Defined Node types are called `Node Bridge' models. For translations between the built-in analog and digital types, predefined node bridge models are included in the XSPICE Code Model Library.