GSM (Global System for Mobile communications) Data   For this connection you will need a dial-up modem, either standard, or GSM. The tracking unit keeps storing your positions internally (up to 250,000 can be stored). These can be retrieved at any time by dialling directly into the unit from your PC. The internal algorithm makes sure that positions are saved only when you move by a set distance and time, so that you do not need to download unnecessary data. With the supplied Navigator tracking software you can execute three basic functions - locate, track and download history. Both locate and track will return live (current) position(s). Your SIM card must be 'data' enabled, which is not default, but easily obtainable free of charge from most operators. To our knowledge only Vodafone provides this service on PAYG SIM cards. As the SIM card only receives calls (if you do not use available alarm features), there is no need to charge the card and the transmission time will be on your BT bill ( if you use BT) just like if you call a mobile phone. On average it takes about 2 minutes to download one weeks history (depending on your settings, distance travelled and travelling time) and should be below £2 per month.