Abstract: A modular offset Automated Testing Equipment (ATE) test head with split backplane is presented. The ATE test head is modularized into a card cage module having a first backplane for accommodating general purpose instrument cards and a cassette module having a second backplane that is offset relative to the first backplane for accommodating personality (specific purpose) instrument cards. The general purpose instrument cards and the personality instrument cards communicates with each other by cables connecting them. The general purpose instrument cards and personality instrument cards can be quickly disengaged from and engaged to the respective backplanes individually or concurrently. Because of this latter feature, a cassette module can be easily and rapidly disengaged from the card cage module and a different cassette module can be easily and rapidly engaged to the card cage module.