GPRS模块，32M的可以支持TTS，而24M的不行

SIM7000c LTE CATM1 EMTC NB-IoT 多模模块,高通芯片

NB-IOT模组，供电电压：2.1V-3.6V，频段同时支持3大运营商网络

3.4~4.2V 128MB -40~+85℃ 24.00 x 24.00mm

SIM7600CE-L 支持移动+电信+联通 4G 3G 2G，无语音，无GPS，有短信

4G CAT1，国内版本，无分集，无GNSS，模拟语音，64Mb，DCXO，1603S

Stable performance, compact appearance, high cost performance, and low power consumption for SMS and data information transmission 3.4~4.2V

Sim7600ce-l1s is a SMT packaged module, which supports lte-tdd / lte-fdd / HSPA + / TD-SCDMA / EVDO and GSM / GPRS / edge Segment, supporting LTE Cat4 (the downlink speed is 150Mbps).

NB-IOT模组

4G CAT1，国内版本，有GNSS，模拟语音，支持屏和摄像头，128Mb，1603E