As part of our continuing research we are now able to offer a passive monitoring system for the encrypted GSM networks. This system is completely transparent in operation to the service provider, maintaining optimum confidentially for the operator. The single channel system is capable of monitoring in excess of two hundred targets simultaneous providing target and correspondent call data TMSI, IMSI, IMEI, dialed number, time and date and two way speech recording of one target. The number of targets can be increased with a three channel version. The system is contained within a discreet carrying case and can be powered by any mains supply or from a car battery.