... Siemens or Huawei GSM module Network GSM, GPRS and SMS ; Voice Headset Kit AvailableMessages SMS, Encrypted Protocol ; GPRS, TCP/IP ... /locking the doors, starting the siren, activating the immobilizer.Voice Call Request Request the unit to call a specific number ... both SMS channel and GPRS channels, also SMS on GPRS, Voice calls.OTA Settings Modification change the communication settings, including APN ...