Personal Communications Service (PCS) - A second-generation digital voice, messaging and data cell phone system in the 2GHz range. PCS is supported mostly by GSM. PCS systems use a different radio frequency (1.9 GHz band) than cellular phones and generally use all digital technology for transmission and reception. "Digital PCS" is a redundancy, as all PCS are digital, but the phrase is used in marketing to distinguish PCS from cellular.