Data communications system with splitterless operation

Abstract

A data communication system that provides different types of service (e.g., telephone services and high-speed data transmission services) to a remote site even when the remote site lacks a splitter is disclosed. A central site (e.g., central office) is able to communicate with at least two different types of remote sites. One type of remote site includes a full splitter (i.e., both low-pass and high-pass filters), and the other type of remote site has only a partial splitter (i.e., includes high-pass filter but lacks a low-pass filter). Although conventionally the transceivers (e.g., ADSL transceivers) at these remote sites would be of the same design and use the same modulation technique for upstream as for downstream transmissions, here the remote site that lacks a low-pass filter (i.e., partial splitter type remote site) uses a different modulation technique for upstream transmissions. As an example, in a data communication system where a remote site lacks a complete splitter, a high peak-average-ratio (PAR) technique like discrete multi-tone (DMT) can be used with downstream transmissions that do not lead to noise at the telephone service even in the splitterless design, and a lower PAR technique (e.g., CPM, QAM, FSK, etc.) can be used with upstream transmissions so that the noise levels produced at the telephone service are vastly reduced. The central site is able to communicate with both the different types of remote sites. The central site selects from various receiver units depending on the type of modulation (e.g., low PAR technique) used.