Could be a typo for PCS, which is similar to GSM but uses the 1.9 GHz band instead of 900 MHz (GSM) or 1.8 GHz (DCS). Unfortunately, I don't think there are dual-mode phones yet.
I think Cynthia is correct (I was transcribing Eric Hughes' Japanese "trip report"). Eric was talking about a very small micro-cell phone extremely popular with Japanese teenagers.
I think its more likely a typo for PHS, or Personal Hand-Phone System, a Japanese micro-cellular system. --begin Churn Hits Japanese PHS Providers, Too Astel/DDI/NTT Personal 09/12/97 The US isn't the only region facing problems relating to churn. In Japan, the PHS providers have been swamped with an avalanche of cancellations according to a South China Morning Post report. Sources at three PHS companies, Astel, DDI and NTT Personal, say the cancellations are a reaction to excessive promotion last year when the US$300 telephones were handed out for as little as a yen each. "People who should never have subscribed to a portable phone service were enrolled and now they are canceling," DDI's Junichi Takahashi said. In addition, August is typically a month for student cancellations, a large segment of the PHS subscriber base, though one analyst said the quality of the service was poor. The report indicates that hundreds of thousands of cancellations almost cancelled out new orders last month, resulting in the lowest net monthly increase to date of 62,000 units. Analysts were not entirely convinced by the explanations offered. Deutsche Morgan Grenfell analyst Naoki Sato said, "The PHS phones are of lousy quality; you often get busy signals or else no signal at all and you cannot use them in cars or trains, so people have begun switching to cellular phones." He said although some analysts expected the PHS system to perish within two years, he thought it would survive as a tool for mobile computing. --end --Steve