TIME DIVISION MULTIPLEX (TDM) SWITCHING SYSTEM ESPECIALLY FOR PULSE CODE MODULATED (PCM) TELEPHONY SIGNALS

摘要

TIME DIVISION MULTIPLEX (TDM) SWITCHINGSYSTEM ESPECIALLY FOR PULSE CODEMODULATED (PCM) TELEPHONY SIGNALSAbstractA TDM switching system for providing selectedconnections between large numbers of lines and trunksand which may combine, in an integrated system, severalTDM switching systems which are adapted to handlesmaller numbers of lines and trunks so as to expand thecapacity of such smaller TDM systems. The system has adistributed, modular architecture in which the lines andtrunks are arranged in a plurality of domains. Thedomains each have a link controller which links thedomains to interdomain PCM highways. The domains eachinclude, as the members thereof, a plurality ofdevices These member devices can be port interfaceswhich connect telephone lines and trunks and convert theanalog telephony signals into PCM signals and viceversa, circuits which provide services, such as tones,conferencing, dual-tone multifrequency (DTMF)facilities, telephony processors which contain the database of the addresses (telephone numbers) of the variouslines and trunks, ringing generators, and interfacedevices which provide a gateway for signals into thedomains for the smaller TDM switching systems. Eachdomain has its own intradomain PCM highway to which thedevices are connected. Each domain may have a differentcomplement of devices The devices are modular andinterchangeable. The architecture provides forcommunication of control signals which control thetelephony signal process along separate links, unique toeach device, which connect that device to the linkML-0174