All 277 underground stations in the subway system are to be wired for cellphone use, the Metropolitan Transportation Authority announced yesterday. But riders may have to talk fast, because the subway tunnels will not be wired, out of consideration for riders who do not want to be stuck in a subway car full of chattering cellphone users. The company that won the right to wire the stations, Transit Wireless, will pay New York City Transit a minimum of $46.8 million over 10 years, the agency said. The company will also pay the full cost of building the wireless network in the underground stations, estimated at $150 million to $200 million. Under the agreement, cellphone providers would pay the company a fee to carry their signals on the network.