近日，通信行业迎来历史性突破——中国电信与中国联通在山东成功打通业界首个跨运营商可溯源 VoWiFi 通话，为解决蜂窝网络室内弱覆盖导致的语音、短信难 题提供跨运营商方案。 即使双方使用不同运营商（如电信用户呼叫联通用户），在 WiFi 环境下也能显示真实号码拨号，通话计入套餐时长，并支持精准溯源保障安全。 早在2022年5月20日，上海电信就成功打通了全球第一个具备端到端带溯源能力的 VoWiFi 电话。 看到这里，可能一些小伙伴对 VoWiFi 比较迷茫，也有人会将其与 VoLTE 和 VoNR 混淆。 VoLTE (Voice over LTE)是一种基于 4G 网络的语音通信技术，它允许语音服务直接通过 4G 网络传输，而不需要回落到 3G 或 2G 网络。 VoNR（Voice over New Radio）则可以看作是 VoLTE 在 5G 时代的升级版，它利用 5G 网络来承载语音服务。相较于 VoLTE，VoNR 在通话质量、接通速度和视频 分辨率等方面都有显著提升。此外，VoNR 在通话过程中不会中断数据连接，确保了语音和数据业务的同时进行。比如玩游戏、观看视频或进行其他需要网络连 接的活动 ...

Group 1 - The article discusses the evolution and significance of dual SIM card functionality in mobile phones, highlighting its origins and the role of Chinese manufacturers in popularizing this feature globally [1][3][5] - The introduction of low-cost chip solutions by companies like MediaTek significantly reduced manufacturing costs, enabling the rapid proliferation of dual SIM phones [3][6] - The demand for dual SIM functionality in China is driven by factors such as varying telecom package costs, the need for separating work and personal numbers, and differences in network coverage among operators [8][10] Group 2 - The article explains the technical aspects of dual SIM technology, including the two main modes: DSDS (Dual SIM Dual Standby) and DSDA (Dual SIM Dual Active), detailing their operational differences [15][17][19] - DSDS allows both SIM cards to be on standby but only one can be active for calls or data at a time, while DSDA enables simultaneous use of both cards for calls and data [19][21] - The advancements in VoLTE and VoNR technologies have enhanced the quality of voice and video calls over 4G and 5G networks, respectively, improving the dual SIM user experience [23][25] Group 3 - The evolution of SIM card sizes from Mini-SIM to Nano-SIM has facilitated the physical implementation of dual SIM functionality in smartphones [29][30] - The design of SIM card slots has transitioned from fixed internal slots to more user-friendly removable trays, allowing for better space management within devices [30][33] - The emergence of eSIM technology represents a significant shift, eliminating the need for physical SIM slots and enhancing device waterproofing and user convenience [37][40][41]