Source: DiCecio, Riccardo
Relative price of equipment is calculated as equipment deflator (https://fred.stlouisfed.org/series/EDEF) divided by consumption deflator (https://fred.stlouisfed.org/series/CONSDEF).
For additional details see: R. DiCecio (2009). "Sticky wages and sectoral labor comovement," Journal of Economic Dynamics and Control, 33(3): 538-53. (http://dx.doi.org/10.1016/j.jedc.2008.08.003).
DiCecio, Riccardo, Relative Price of Equipment [PERIC], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/PERIC, January 18, 2018.