US Patent 9665870 Multi-input tamper detection system

A payment reader includes a tamper detection system for monitoring and protecting against attempts to tamper with the payment reader. The tamper detection system includes tamper detection devices such as tamper switches or tamper meshes, and tamper detection circuitry to control and interface with the tamper detection devices. Pulses are selectively provided from each of a plurality of tamper pins of the tamper detection circuitry to an associated tamper detection device, and a tamper attempt is identified if that pulse is not received at an associated tamper pin. All other tamper pins are switched to an input state, and a tamper attempt is also identified if an aberrant signal is received at the tamper pins while in the input state.