No. 10A Remote Switching System: Host Software

A local Electronic Switching System (ESS) provides the call control for a 10A Remote Switching System (RSS). The 10A RSS acts as a slave executing orders sent to it from the host ESS and reports events, such as line originations, to the host. A major advantage of this type of distributed control is that the complex tasks of call processing can use existing host software and share host equipment and trunking facilities. This sharing of host ESS software provides the capability of easily providing RSS lines with the sophisticated features that are offered to host ESS lines. Figure 1 shows the system configuration consisting of a host ESS office, a 10A RSS (remote terminal), a data link controller, interconnecting voice channels, and data links. The data links are used for communication between the host ESS and the 10A RSS, and provide the means by which orders from the host are transmitted to the 10A RSS and acknowledgments are returned to the host. Voice channels are used to provide the RSS lines with access to the host network and are selected dynamically. In the No. 1 ESS RSS host implementation, the 491