Seoul - North Korea has welcomed foreign visitors and firms to a trade fair this week, showcasing homegrown products including the latest model of its sleek Jindallae smartphone.Diplomatically isolated and under biting sanctions over its nuclear and weapons programs, North Korea has an aging manufacturing base that analysts doubt has the ability to make high-quality consumer technology.Still, Pyongyang has touted Jindallae — 'azalea' in Korean — as a convenient way for citizens to stay connected, albeit through a strictly controlled domestic network.