Diagnostic method of equipment and system using the same

• US 4,858,224 A
• Filed: 01/05/1988
• Issued: 08/15/1989
• Est. Priority Date: 01/09/1987
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Nakano, Yukio, Kanno, Tadayuki
• Primary Examiner(s): Olms, Douglas W.
• Application Number:
  US07/140,791
• Time in Patent Office: 588 Days
• Field of Search: 370/16, 370/13, 370/14, 371/11, 371/22
• US Class Current: 370/217
• CPC Class Codes: H04J 3/14 Monitoring arrangements for SDH/SONET rings H04J3/085
• CPC Class Codes: H04Q 11/04 for time-division multiplexing H04Q11/0001 takes precedence

Abstract

In a digital switching equipment or a digital cross-connect equipment including a plurality of receiving circuits, a multiplexer, a time division switch, a demultiplexer, and a plurality of transmitting circuits, each of the receiving circuits or the multiplexer has a circuit to insert a specific sequence into filling time slots of a plurality of subhighways of a highway having a plurality of time slots and each of the transmitting circuits and the demultiplexer has a circuit to detect the specific sequence inserted into the filling time slots such that when either one of the error detect circuits detects an error, a route change of the filling time slots is accomplished by means of a time division switch so as to predict a location of occurrence of a failure depending on a change in a detection state of the error detect circuits in association with the route change.

Claims

1. A diagnostic method in a line equipment including a plurality of receiving circuits for receiving respective input signals and for converting the input signals into a plurality of sub-highways, a multiplexer connected to said plurality of receiving circuits for multiplexing the sub-highway to configure a highway having a plurality of time slots, a time division switch connected to said multiplexer for exchanging time slots of an information sequence including said highway, a demultiplexer connected to said time division switch for demultiplexing said highway outputted from said time division switch into a plurality of sub-highways, and a plurality of transmitting circuits connected to said demultiplexer for respectively transmitting said sub-highways, comprising the steps of:

providing each of said receiving circuits with a circuit for inserting a specific sequence into filling time slots of a corresponding sub-highway;

exchanging, by said time division switch, each filling time slot over a specific route in accordance with said specific sequence inserted therein;

providing each of said transmitting circuits with an error detection circuit for detecting whether an error exists in said specific sequence inserted into filling time slots supplied by a specific route, wherein each of said error detection circuits are connected to a specific route by said time division switch;

effecting, when one of said error detection circuits detects an error, a route change of the filling time slots supplied thereto by said time division switch; and

predicting a location of occurrence of a failure depending on a change in a detection state of said error detection circuits in association with said route change.

2. A method according to claim 1, wherein said specific route is connected to said error detection circuit in accordance with said specific sequence inserted into said filling time slots.

3. A diagnostic system of a line equipment including a plurality of receiving means for receiving respective input signals so as to convert the input signals into a plurality of sub-highways suitable for a switching operation, multiplex means for multiplexing said plurality of sub-highways to configure a highway, switch means for exchanging time slots of an information sequence constituting said highway, means for demultiplexing said highway outputted from said switch means into a plurality of sub-highways, and transmitting means for respectively transmitting said sub-highways, comprising:

a plurality of test signal generators for inserting a specific sequence into filling time slots of a frame format of the sub-highway converted by each receive means;

a plurality of error detection means for checking said specific sequence inserted into the filling time slots of the frame format of the sub-highway received by each transmitting means;

diagnostic means for receiving a detection signal from each of said error detection means to determine an interval where failure has occurred; and

switch control means for exchanging the filling time slots of said switch means depending on an output from said diagnostic means.