I only ask out of pure curiosity. I have an old, nonworking CM15A that I can't bring myself to throw away but will probably never have a reason to replace.
...unless Dave Houston finishes his "ZBasic Arduino on crack" mod; then it's going back on the bench!
My mod replaces the Cypress MCU, the RF receiver, RF transmitter and adds USB-SER & RTC chips (all on a daughterboard).
It keeps the power supply, PLC & ZC interfaces, 120kHz oscillator and AGC circuitry. You will need to replace the antenna with a 50-ohm BNC connector, replace the EEPROM with a bigger one, replace the MCU with a DIP-18 socket and plug in my daughterboard. The RTC only needs 3V so the easiest thing to do is use 2 dummy AAA
batteries (rather pricey but they do last forever). I'll design a kit with all necessary parts. You can use a telescoping antenna with a BNC base or an eggbeater antenna (minimal assembly required) available in kits (both non-amplified and amplified, w/5V via the coax, supplied by the daughterboard through a resettable fuse).
There's an optional ESP8266 based external unit (powered by a 5V power supply with microUSB plug) that provides a WiFi link and NTP time.
There are drivers for Windows, OSX & Linux which provide a virtual COM port and I'll document the communication protocol. Anyone who prefers Arduino code can reflash the ATmega328 with the Arduino bootloader and write their own code. The ESP8266 can also be Arduino-ized. I'll document the timing for the AGC Window & AGC Reset signals for those prefer the Arduino world.
I'll try to update some Windows, OSX & Linux applications I created earlier for some other X10 related hardware. I'll likely leave mobile apps for others as I find tablets and smart phones difficult with one hand paralyzed.
For those with and without soldering skills, this is highly recommended...
http://www.amazon.com/Velleman-VTDESOL3U-Vacuum-Desoldering-Heater/dp/B00B88FRMEYou'll need basic soldering skills and a 25-35W soldering iron for the EEPROM & DIP-18 socket.