Huh?

I didn't say anything about 900. I said 800 = 850. I said that because "800" and "850" are two terms for the exact same swath of spectrum. It's the cellular band, the original mobile-phone band in the U.S. There are two cellular and six PCS (1900) licenses for any given area of the country.

850 (AKA 800) is deployed in EVERY urban and rural area of this country where there is any cellular service at all. It's the spectrum used by the old analog (AMPS) systems, and CDMA and TDMA have been deployed there in various cities for many years, and now GSM is simply being deployed in this same spectrum as well.

900 is used for totally different things in this country (not cellular phones). When people talk about GSM 900, they're talking about Europe, Asia, Africa, etc.

You mentioned public safety issues. That's a conflict only with Nextel, which uses separate spectrum from what people usually refer to as "800", "850", or "900". There is no conflict between GSM 850 and public safety or businesses.