Taking its Soviet venture a stage further, Bell Atlantic Corp signed an agreement in Leningrad yesterday with the Russian Ministry of Communications, Leningrad City Council and various local and international telephone companies to develop a cellular phone system, an international gateway and upgrade the city’s existing telecommunications infrastructure; Bell Atlantic says it is to lead and co-ordinate all Western companies working on telecommunications in Leningrad: plans for the cellular network, packet data network and gateway should be completed by the end of the month.