Abstract: A digital subscriber line (DSL) system that provides fast exit from an idle state includes a central office (CO) modem for communicating with a customer premises equipment (CPE) modem. Prior to entry into a low-power or idle state for the DSL link between the CO modem and the CPE modem, seamless rate adaptation is performed in order to improve the operating margin from that used in full-on operation, for example by selecting a reduced data rate. Transmission parameters, including data rate, and bits and gains, and corresponding to the improved operating margin are stored at the modems. Upon executing short initialization to return from the idle state, the stored transmission parameters are more likely to be adequate to meet current channel conditions, so the exchange of transmission parameters during short initialization is more likely to be avoided.

Abstract: A digital subscriber line (DSL) system that provides fast exit from an idle state is disclosed. The system includes a central office (CO) modem for communicating with a customer premises equipment (CPE) modem. Prior to entry into a low-power or idle state for the DSL link between the CO modem and the CPE modem, seamless rate adaptation is performed in order to improve the operating margin from that used in full-on operation, for example by selecting a reduced data rate. Transmission parameters, including data rate, and bits and gains, and corresponding to the improved operating margin are stored at the modems. Upon executing short initialization to return from the idle state, the stored transmission parameters are more likely to be adequate to meet current channel conditions, so the exchange of transmission parameters during short initialization is more likely to be avoided.

Abstract: A system and method for reordering tones of a DMT signal within a communication system is described. Cross tone correlated noise in a received signal is identified and rearranged such that tones with correlated noise are spread out throughout the received signal before being processed by a decoder such as, Viterbi decoder. In an embodiment, two tones with the most correlated noise are placed at each end of the sequence of tones presented to the Viterbi decoder. In some embodiment, the tones with correlated noise can be spread such that two adjacent tones with correlated noise have a minimum distance of at least three tones between them at the input to the Viterbi decoder. In other embodiment, tones in the received signal can be processed in various kinds of interleavers for reordering according to the interleaver scheme.

Abstract: Method for preventing a facsimile server from looping back on itself, the method including the steps of: (a) transmitting fax server identifier information during fax transmission setup; (b) analyzing the fax server identifier information to determine whether the fax server identifier information is the same as that of the fax server that is placing the call; and (c) if the fax server identifier information is the same, dropping the call, otherwise, continuing the call. In a preferred embodiment, the fax identifier information is transmitted in the NSF command of the facsimile communication protocol.

Abstract: A system and a method are provided for detecting a type of a received signal. The system includes a processor (32) and two receivers (24, 26). Both receivers (24, 26) are coupled to the processor (32). The first receiver (26) is capable of receiving a first signal type, and the second receiver (24) is capable of receiving a second signal type. An algorithm (30), coupled to the second receiver (24), is used for distinguishing between the first signal type and the second signal type. The algorithm (30) is used after the first receiver (26) begins storing the signal as a first signal type, and after the second receiver (24) begins storing the signal as a second signal type. At least one of the two signal types is retained.

Abstract: The reliability of call transfer in a PBX can be improved by verifying the availability of a destination port before a transfer is attempted. The incoming call is routed to an alternate line after the interrogation occurs. Once the availability of the desired facility is confirmed, the call can be picked up by the destination port.

Abstract: By testing a received signal for power, frequency content, and stability, one can measurably improve DTMF signal detection and identification performance in voice store and forward systems. The algorithms described here have been found to be especially useful in minimizing talk-off. Further, the approach improves the performance with acoustic-type generators and minimizes transhybrid loss.

Abstract: Apparatus for detecting and identifying DTMF signals in connection with a voice store and forward equipment (VSF) and for preventing talk-off, whether generated by the VSF or by a user of the VSF.

Abstract: The detection of DTMF tones is improved in a three-step process: first testing even-numbered samples; then testing odd-numbered samples, and finally testing for tone quality (time interval and frequency stability).

Abstract: A method for dividing a message into a plurality of message blocks and storing each of the plurality of message blocks on separate units within a distributed data storage system. Facilities for retrieving the information from the distributed data storage system and recreating the original message for replay are also provided. If a unit within the distributed data storage system fails, then a degredated version of the original message is recreated from the remaining units and their stored message blocks.

Abstract: Method and apparatus for sectionalization and self-diagnosis of loop start and ground start trunk interfaces without intervention from host telephone company equipment. The inventive method entails the use of an isolation relay in the trunk circuit to isolate the trunk circuit electrically from the physical medium and to apply various signals to portions of the isolated trunk circuit to carry out specific self-diagnostic tests.