Final answer:
GSM phones use SIM cards, while PSTN and CDMA phones do not.
Step-by-step explanation:
Phones that use SIM cards include GSM phones. GSM stands for Global System for Mobile Communications, and it is a standard for mobile phone networks. SIM stands for Subscriber Identity Module, and it is a small smart card that contains the user's identity and information. When you insert a SIM card into a GSM phone, it allows you to connect to the mobile network and make calls, send messages, and access data.
Other types of phones, such as PSTN (Public Switched Telephone Network) phones, don't use SIM cards. PSTN phones are landline phones that are connected to a traditional telephone network. CDMA (Code Division Multiple Access) phones also don't use SIM cards. CDMA is another standard for mobile phone networks, and these phones use a different technology to connect to the network.
In summary, GSM phones use SIM cards, while PSTN and CDMA phones do not.