Hot mobile phone brands with dual card slots in 2003

Multi-card two-way sending and receiving mobile phone. The popularity of dual-card slot began with 1994. Nokia applied for a patent, and then it became popular in the dual-card slot mobile phone market in China. The most popular brand in 2003 was the mobile phone brand submitted by Hong Chuantian, that is, multi-card two-way sending and receiving mobile phones. The idea of this patent is to provide a multi-card bidirectional transceiver.