Adtran Gmbh

Clifford L Hall

Jeffrey B Wells

Norman R Harris

Stephen T Killian

Scott C Bailey

David L Mack

Michael W Elliott

The problem of digital data corruption heat occurs when an analog card is inserted into a card/time slot of a D4 channel bank is effectively remedied by sampling and analyzing the channel bank's transmit enable (TNEN) lead for successive frames of time slots. Unless analyzed TNEN lead samples of a channel unit time slot of interest derived over successive frames have the same logic state associated with an analog channel unit, the PCM data lead remains default-coupled to a digital data transmission lead. This prevents PCM-encoded spurious noise on the analog PAM lead from being erroneously asserted in place of serialized digital data bits that should have been passed directly from the digital data bus to the PCM bus.

Reduction of errors in D4 channel bank by multiframe comparison of

A performance monitoring arrangement conducts auxiliary in-band communications between a line interface unit and one or more channel units of a D4 channel bank without interrupting transmission of digital data to and from a customer premises. During a first, initialization mode of operation, and a second, smart performance-monitoring mode, the data communication format of a channel bank RNPCM bus is modified to allow insertion of an auxiliary line interface unit-sourced command bit between selected bits of the data. During the second mode of operation, the communication format of the channel bank link is further modified to provide for the transmission of the data at an increased data rate. This increased data rate permits a response message bit from the channel unit to be asserted on the RNPCM bus during a first time interval separate from that occupied by the increased rate data. During the smart mode, the line interface unit also controllably asserts a yellow alarm code signal onto the RNPCM bus during a second time interval that is separate from the first time interval and that occupied by successive bits of increased rate data.

D4 channel bank with multi-mode formatted, performance-monitoring

Non-intrusive performance monitoring of a DS0 channel between a customer premises interface and a D4 channel bank includes an augmentation of existing channel bank equipment and a digital services communication device terminating the DS0 link at the customer site. An auxiliary signalling and performance monitoring arrangement is remotely accessible by a non-resident control site, for example by way of an RS-232 port of a line interface unit of the channel bank, thereby enabling the control site to perform prescribed network supervisory tasks with respect to one or more selected DS0 links, including provisioning of their associated loop equipment and performance monitoring of each DS0 loop. Office channel unit data port and line interface components of the channel bank are modified to provide bidirectional signalling capability via the receive segment of the channel bank's internal communications link. The signalling format on the bidirectional signalling link is defined so as to support both the transmission of incoming (received DS1) signalling traffic from the line interface unit to an office channel unit, and the bidirectional exchange of performance-monitoring command and response messages. A performance monitoring arrangement, installed in the channel unit and the digital communications network interface, monitors at least one prescribed performance aspect of the DS0 channel and forwards performance signals to the line interface unit over the bidirectional signalling link.

Performance monitoring of DSO channel via D4 channel bank

A bleedover prevention circuit prevents a low data value of the last bit of an occupied channel unit time slot from bleeding over into the first and second bit times of an unoccupied channel unit time slot of a channel bank, by forcing the data lead to a high logic level within a terminal portion of the last bit time of an occupied channel unit time slot. The terminal portion of the last bit time occurs within a time interval delayed relative to a sampling clock edge, so that it does not detrimentally impact the validity of the value of the last data bit. If the immediately succeeding channel time slot is unoccupied, driving the data lead high prior to the beginning of such unoccupied channel time slot will render immaterial whether the last data bit value of the occupied channel time slot is a `one` or a `zero`, and will serve to effectively overcome the relatively long charging time, that would otherwise be required to pull the data lead high if the last data bit value were a `zero`.

Channel unit transmission for removing false data bits in adjacent

Non-intrusive performance monitoring of a DS0 channel between a customer premises interface and a D4 channel bank includes an augmentation of existing channel bank equipment and a digital services communication device terminating the DS0 link at the customer site. An auxiliary signalling and performance monitoring arrangement is remotely accessible by a non-resident control site, thereby enabling the control site to perform prescribed network supervisory tasks with respect to one or more selected DS0 links. Office channel unit data port and line interface components of the channel bank are modified to provide bidirectional signalling capability via the receive segment of the channel bank's internal communications link. The signalling format on the bidirectional signalling link is defined so as to support both the transmission of incoming (received DS1) signalling traffic from the line interface unit to an office channel unit, and the bidirectional exchange of performance-monitoring command and response messages. A performance monitoring arrangement, monitors at least one prescribed performance aspect of the DS0 channel.

Performance monitoring of DS0 channel via D4 channel bank

A digital tandem channel unit installable in an intermediate central office of a digital carrier telephone network maintains the digital format of the T1 traffic in the course of a DS0 tandem cross-connect, so as to eliminates the possibility of corruption of voice/data traffic, as may occur in a conventional `analog` office cross-connect tandem pair due to quantization errors introduced into the data stream in the course of the digital to analog conversion of the data. Also, the invention incorporates control software in each tandem channel unit's micro-controller that allows it to respond to analog tone signalling test procedures initiated from either two or four-wire channel ports of network access equipment.

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Huntsville, AL, United States of America

Clifford L Hall