The deployment and investment of telecom in the mobile terminal is far less than that of China Mobile and China Unicom. Most of the base stations on the mobile side of telecom adopt Unicom technology and equipment, especially the 4G network. Frankly speaking, it can be understood that telecom users give money to telecom and telecom gives part to Unicom. This is strategic cooperation, but Telecom 4G≠ Unicom 4G. Due to commercial monopoly and other reasons, although China Unicom and China Telecom both adopt FDD-LTE standard, China Unicom's mobile phone does not support telecom cards, and China Telecom's mobile phone does not support China Unicom's 4G (except the full netcom version). The so-called "dual 4G" refers to the support of China Unicom's 4G and mobile 4G, while China Telecom's 4G is only supported by China Telecom's mobile phone and full netcom version.
Telecommunication equipment is made in Qualcomm, Qualcomm has an absolute monopoly position in EV-DO network (i.e. telecommunication CDMA network), and Qualcomm will charge 4% telecommunication patent fee (I don't know how much now), so mobile phone manufacturers can only wait for the price reduction of Qualcomm chips before joining the telecommunication standard, and it is reported that the chip monopolist Qualcomm has definitely given up the research and development of CDMA-4G. At the same time, there are fewer and fewer countries with CDMA networks in the world, and only GSM cards can be replaced when roaming internationally. Therefore, most mobile phones will not launch the CDMA version for the first time.