Why GPS Tracker need a SIM card ?

Why gps tracker need sim card?

--GPS device is a mini Featured phone system , just without the keyboard .GPS device system consist of mini phone system+GPS modue +Wifi modue.GPS device work with smart phone app and Cloud server, all GPRS communications via. Sim card through Operator Cellular 's network. It's available for global real time and real Googlemap tracking if the sim is available for international roaming. GPS work with smart phone app is phone to phone.

--Any GPS Tracker has a receiver to triangulate its own position from the satellite signals. All the GPS trackers need a SIM card in order to achieve connectivity. SIM cards are what allow location transmission, sending audio data, and receiving commands to turn on audio and other advanced features.

Sim card specifications:

1) If the GPS device is 2G system, it need 2G/GSM compatible SIM (it's ok for 4G/5G SIM card, but need check with SIM card Operator , and ensure the 4G/5G SIM card is fully compatible with 2G/GSM network is fine, also activate GSM GPRS pre-paid monthly plan )

2) 2G/GSM Frequency bands: 800/850/1800/1900MHZ
3) Activate GSM GPRS Flew package monthly, no less than 25-30MB/month

4) If GPS device is 4G system, just use the 4G Nano sim card , VOLTE sim valid Voice +SMS +GPRS 
5) Available for international roaming if necessary.
6) Without PIN code, nor voice mail 
7) Voice +SMS+GPRS  SIM card
8) Please kindly get the APN,MCC and MNC code from your SIM card/phone operator,because later on you need the correct APN information for local setting.