Cable builds in microphone and automatically picking up phone call system. After calling the micro SIM card phone number which inserted in cable, you can hear the people's communication around the cable.</br>Use text command to control the GPS cable to get location or set up Voice-activate Callback. (Greater than 45db)</br>Jiusion GPS cable is also a real cable which can provide the speed possible charge via USB charger and sync data to your computer.</br>Cable only works when it connected with external power supply like car or wall charger, power bank. It has not battery inside.</br>Device Work frequency: GSM 850Mhz/900Mhz/1800Mhz/1900Mhz (Quad-band).GSM SIM card doesn't include.(1pcs 10% off, enter code "G76L2BGH", 2pcs 20% off, enter code "MPZ8B897")</br></br>Product Description</br></br><br>This GPS tracker requires a GSM Sim card for 850/900/1800/1900MHZ. It <b>only supports 2G SIM card. </b>The package does NOT include a sim card; you must purchase your own sim card.<br><br>First of all, you need to insert an active SIM to cable. Your personal mobile can call this SIM phone number and hear the voice around the cable at any time. <br><br> Get GPS location: Use personal mobile to text "DW" to the cable's phone number and you can get location information. <br> <br>Set up Voice-activate Callback: Text "1111" and send to the cable's phone number. When cable's environment is larger than 45db, cable will automatically call your personal mobile and you can hear the sound at that moment. <br> <br>Cable Compatible With: iPhone 7/7 Plus/6/6 Plus/6S/6S Plus,SE/5S/5,iPad,iPod Nano</br><br/>http://www.amazon.com/gp/product/B06X42SGPY