DTMF receiver sense and control maintenance arrangement

In a telecommunications switching system having a network clock, a DTMF receiver maintenance arrangement is connected to a plurality of DTMF receivers which interface customers to said switching system for transmitting data to said switching system, said DTMF receiver maintenance arrangement operable for determining proper operation of a DTMF receiver arrangement, said DTMF receiver maintenance arrangement comprising:

• a processor;
• control means connected to said processor, said control means being operated to store and to transmit data from said processor and to said processor;
• sense means connected to said processor, said sense means being operated to store data and to transmit said stored data to said processor;
• sequencing means connected to said network clock, said sequencing means being operated in response to said network clock to produce a plurality of regularly defined time slots during a DTMF receiver sampling cycle;
• last look means connected to said plurality of DTMF receivers, to said sequencing means and to said network clock, said last look means being cyclically operated during each said time slot in response to said sequencing means to produce and to store an indication of whether a particular DTMF receiver has been previously sampled for valid data during a current DTMF receiver sampling cycle;
• generating means connected to said control means, to said last look means and to said sequencing means, said generating means being operated in response to said indication of said last look means that said particular DTMF receiver has been previously sampled during said current DTMF receiver sampling cycle, to inhibit production of a write signal and said generating means being further operated in response to an indication of said last look means that said particular DTMF receiver is to be sampled during a corresponding time slot of said current DTMF receiver sampling cycle, to produce said write signal;
• storage means connected to said plurality of DTMF receivers, to said sequencing means, to said generating means and to sense means, said storage means being operated in response to said write signal to store said data from a particular DTMF receiver druing said corresponding time slot and said storage means being further operated to transmit said stored data of each DTMF receiver to said sense means for retransmission to said processor;
• maintenance means connected to said control means, to said sequencing means, to said last look means, to said generating means and to said storage means, said maintenance means being operated in response to a request from said processor to transmit maintenance data to said storage means during a particular specified time slot for said retransmission to said processor;
• and
• said processor being operated in response to said retransmitted data to compare said retransmitted data with said maintenance data for determining said proper operation of said DTMF receiver arrangement.