Public CT2 system with two-way calling

In the current implementation of most CT2 systems, only handset initiated calls are allowed. The paper describes a design to allow two-way calling for the CT2 system with minimal modification to the current CT2 infrastructure as well as the public switched telephone network (PSTN). The design makes use of centralized databases in home location register (HLR) and visitor location register (VLR) to track the location of the handsets. A diagram of the CT2 two-way calling system is depicted. The authors also did a computer simulation of the proposed system to determine the potential area of congestion in the system