A specification for a power meter states that it provides KYZ pulse outputs.
Utility Meter with KYZ pulse outputs
Some meter specification sheets may state that the device outputs KYZ pulses.
KYZ is a designation given to a relay used to create pulses for electrical metering applications. It is commonly a Form C relay (SPDT). The term KYZ refers to the contact designations: K for common, Y for Normally Open, and Z for Normally Closed.