For questions about hardware or software that you use specifically to enable your teaching. This could be networking, collaboration (but not GIT), screen-casting. Don't use this for the hardware you teach on (arduino, pi) , or the software students use directly (IDE or interpreters)
Classroom infrastructure includes hardware and software that you use to support teaching, not the things taught. Examples from the olden days would be overhead (foil) projectors. More modern examples are things like TeleCoil for the hearing impaired and screen projectors. For the younger student, even physical objects used to teach computational thinking might apply.