Where can I find the MAC ID and MAC CRC codes needed to register my thermostat?
The MAC ID and MAC CRC will show in the message center of the thermostat. The numbers are also included on the Thermostat ID Card packed with the thermostat, or on the back of the thermostat when it is removed from the wallplate. Each thermostat has a unique MAC ID and MAC CRC. (Page 60)
From the official Honeywell RET97B5D100 Home Programmable Thermostat manual, page 60
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