Muldem with monitor testing on-line and off-line paths

A demultiplexer with an improved monitoring system for the detection of malfunctions, comprising in combination:

• a plurality of parallel data output groups;
• normally on-line reception means demultiplexing serial high speed input data for parallel transmission over said groups;
• standby data protective switching means providing an alternate standby data path configuration around said reception means upon malfunction of the normally on-line data path configuration through said reception means, and including auto-revert means automatically restoring said data path to said normally on-line configuration upon correction of said malfunction;
• and
• monitor means testing data paths through said demultiplexer for detection of malfunctions in said demultiplexer, and including a latched display of said malfunction after said automatic restoration from said standby configuration to said normally on-line configuration by said auto-revert means, to provide an indication of a corrected malfunction.

A muldem with an improved monitoring system for the detection of malfunctions, comprising in combination:

• a plurality of parallel data input transmission groups;
• normally on-line transmission means multiplexing said data input transmission groups for serial transmission of high speed data;
• a plurality of parallel data output reception group;
• normally on-line reception means demultiplexing serial high speed input data for parallel transmission over said data output reception group;
• standby data protective switching means providing an alternate data path configuration around said transmission or reception means upon malfunction of the normally on-line data path configuration through said transmission or reception means, and including auto-revert means automatically restoring said data path to said normally on-line configuration upon correction of said malfunction;
• and
• monitor means testing data paths through said muldem for detection of malfunctions in said muldem, and including a latched display of said malfunction after said automatic restoration from said standby configuration to said normally on-line configuration by said auto-revert means, to provide an indication of a corrected malfunction.

A multiplexer comprising:

• a plurality of parallel normally on-line main input group means receiving input rate data;
• normally on-line main high speed transmitter means multiplexing said input group means for transmission of high speed data;
• normally off-line standby means capable of switching to provide an alternate data protecting path through the multiplexer;
• and
• means for selecting data from said input rate data and, before switching to said alternate path, periodically connecting the selected data from said input group means to said standby means, without interfering with the multiplexing and transmission of the selected data by said main means, and comparing data bits at an output of said standby means with data bits at an input thereof, thereby testing against a silent failure of the standby means.

A multiplexer comprising:

• a plurality of parallel normally on-line main input group means receiving input rate data;
• normally on-line main high speed transmitter means multiplexing said input group means for transmission of high speed data;
• normally off-line standby means capable of switching to provide an alternate data protecting path through the multiplexer replacing one of said main means;
• and
• means for selecting data from said input rate data and, after switching to said alternate path, connecting the selected data to a path including said replaced main means, without interfering with the multiplexing and transmission of the selected data by the main and standby means which are on-line after switching, and comparing data bits at an output of said path including said replaced means with data bits at an input thereof, thereby testing for proper operation in the path including the replaced means.

A demultiplexer comprising:

• a plurality of parallel normally on-line main output group means providing output rate data;
• normally on-line main high speed receiver means demultiplexing serial high speed data for parallel transmission by said output group means;
• normally off-line standby means capable of switching to provide an alternate data protecting path through the demultiplexer;
• and
• means for connecting, before switching to said alternate path, bits from said high speed data to said standby means, without interfering with the demultiplexing and transmission of the connected bits by said main means, and comparing data bits at an output of said standby means with data bits at an input thereof, thereby testing against a silent failure of the standby means.

A demultiplexer comprising:

• a plurality of parallel normally on-line main output group means providing output rate data;
• normally on-line main high speed receiver means demultiplexing serial high speed data for parallel transmission by said group means;
• normally off-line standby means capable of switching to provide an alternate data protecting path through the demultiplexer replacing one of said main means;
• and
• means for connecting, after switching to said alternate path, bits from said high speed data to a path including said replaced main means, without interfering with the demultiplexing and transmission of the connected bits by the main and standby means which are on-line after switching, and comparing data bits at an output of said path including said replaced means with data bits at an input thereof, thereby testing for proper operation in the path including the replaced means.

A muldem comprising:

• a plurality of parallel normally on-line main input group transmit means receiving input rate data;
• normally on-line main high speed transmit means multiplexing said input group means for transmission of high speed data;
• normally off-line transmit standby means capable of switching to provide an alternate data protecting transmit path through the muldem;
• a plurality of parallel normally on-line main output group receive means providing output rate data;
• normally on-line main high speed receive means demultiplexing serial high speed data for parallel transmission by said output group means;
• normally off-line receive standby means capable of switching to provide an alternate data protecting receive path through the muldem;
• means for connecting, before switching to said alternate path, bits of said input rate data to said transmit standby means, without interfering with the multiplexing and transmission by said main transmit means, and comparing data bits at an output of said standby transmit means with data bits at an input thereof;
• and
• means for connecting, before switching to said alternate path, bits from said high speed data to said receive standby means, without interfering with the demultiplexing and transmission of said main receive means, and comparing data bits at an output of said receive standby means with data bits at an input thereof, thereby testing against a silent failure of said standby means.

A muldem comprising:

• a plurality of parallel normally on-line main input group transmit means receiving input rate data;
• normally on-line main high speed transmit means multiplexing said input group means for transmission of high speed data;
• normally off-line transmit standby means capable of switching to provide an alternate data protecting standby path through the muldem replacing one of said main transmit means;
• a plurality of parallel normally on-line main output group receive means providing output rate data;
• normally on-line main high speed receive means demultiplexing serial high speed data for parallel transmission by said group receive means;
• normally off-line receive standby means capable of switching to provide an alternate data protecting standby path through the muldem replacing one of said main receive means;
• means for connecting, after switching to one of said alternate paths, data bits selected from said input rate data and said serial high speed data to a path including the main means replaced, without interfering with the processing of the connected bits by the main and standby means which are on-line after switching, and comparing data bits at an output and an input of the path including said replaced means, thereby testing for proper operation in the path including the replaced means.