This is a plug-in daughterboard that replaces the Cypress CY7C83723 microcontroller used in the CM15A with a PIC16F87, converting the input/output to RS232 TTL. In addition to X-10 PLC send/receive, it provides access to all of the CM15A hardware including the RF receiver and RF transmitter as well as the 2KB EEPROM. The CM15X-S incorporates a bootloader so firmware updates can be done via RS232. The CM15A schematic can be found here. It will report all X-10 RF (standard and security) and, if the superheterodyne RF receiver in the CM15A is replaced with a wideband superregenerative RF receiver (RM1SG), can report RF from other RF devices in the 305-325MHz range. NOTE: Unlike the superheterodyne receiver, the referenced superregenerative receiver does not work well with a wideband preamp. Both can be improved with a more efficient antenna.

NOTE: This approach retains the CM15A's isolation from the mains voltage and does not affect the FCC approval.

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