Dynamically-assigned voice and data channels in a digital-subscriber line (DSL)

This invention relates to telephone systems, and more particularly to Digital-Subscriber Lines (DSL) carrying both voice and data traffic. A Digital-Subscriber Line (DSL) modem dynamically allocates its bandwidth to voice calls or data traffic as needed. Low-level frames are divided into several 64-Kbit/sec timeslots, each able to carry one voice call. These low-level frames are repeated several times in a 1-KHz frame that is synchronized to network timing references such as an 8-KHz clock used by the telephone network's pulse-code-modulated (PCM) highway. The 1-KHz frames are grouped into superframes. The low-level timeslots are allocated to either voice channels or to unchannelized data, depending on the number of voice calls currently being made. Allocations are made once for each superframe. The allocations or assignment of each of the timeslots to either voice or data is determined and sent to the remote modem or line card before the next superframe begins. When a good CRC occurs, the allocation sent is used to format the next superframe. Allocation bits for each of the timeslots indicate that the timeslot is for voice or for data. Different line and data rates result in different numbers of the 64-Kbit timeslots. Formats of the 8-KHz frames and superframes are fixed. The superframes contain framing bits that carry the next superframe's allocation to the remote modem.