I have completed a layout for the signal adapter board to connect an LPFRS or LPRO compatible rubidium oscillator (or any general purpose Rb) to my X72 BNC connector/RS232 board . The LPFRS is a small rubidium oscillator. It is usually sold mounted on a heatsink with a small board that provides an LPRO compatible connector, except it replaces the lamp and xtal voltage monitoring pins with a serial interface. My interface board can replace the LPFRS board or it can be connected via the LPRO connectors. It has support for an EFC voltage setting pot that provides 0-5V (or you can use the EFC input BNC on the connector board). It also has a PICDIV chip for generating a 1PPS output. When used with the LPRO or an oscillator that does not have a serial port (or you don''t want to use the LPFRS serial port) the board also has a place for a PICPET timestamping time interval counter chip.