Telephone dial-inbound data acquisition system with demand reading capability
First Claim
1. Apparatus for transferring data over a telephone network comprising:
- a remote data unit; and
a host computer, said remote data unit and said host computer being interconnected over a telephone network;
said remote data unit including;
a) timing means for generating a time signal in a pseudorandom manner;
b) real time clock means for generating an indication of real time;
c) means for comparing said real time with said pseudorandomly generated time signal;
d) means responsive to said comparison between said real time and said pseudorandomly generated time signal for accessing said telephone network when said real time bears a predetermined relationship to said pseudorandomly generated time signal; and
e) means for transferring data from said remote data unit to said host computer, said transferring means further transferring a subsequently generated pseudorandom time signal generated by said timing means to said host computer;
said host computer including means for receiving and comparing said subsequently generated pseudorandom time signal with a table of allowable times, said host computer further including means for sending an indication back to said remote data unit of whether the time indicated by said subsequently generated pseudorandom time signal is acceptable as shown by said comparison with said table of allowable times and, if so, said time is accepted as the next time of callback for said remote data unit and, if not, said host computer sending an indication to said remote data unit to cause said timing means to generate another pseudorandomly generated time signal, said host computer storing an indication of the acceptable time of callback for said remote data unit in said table of allowable times.
7 Assignments
0 Petitions
Accused Products
Abstract
A telephone dial-inbound data acquisition system with demand reading capability. The system has particular application for remotely reading utility meters. A remote data unit (RDU) dials up a host computer on a periodic basis. The RDU is assigned a callback start time by the host computer. The RDU calculates an actual callback time based on the callback start time and a randomly generated time delay. The RDU dials up the host computer via a modem when the local time, as shown by an on-board real-time clock at the RDU, equals the calculated actual callback time. Meter reading data is then transferred to the host computer. The RDU also contains circuitry for detecting a polling signal generated by the host computer. Upon detection of this polling signal, the RDU immediately dials back the host computer and transfers utility meter reading data to the host computer. The RDU will also immediately dial back the host computer if an alarm condition occurs, e.g. tampering or a low battery condition. The RDU contains circuitry for characterizing the on-hook and off-hook electrical characteristics of the telephone line to ensure that the RDU does not interfere with normal operation of a customer'"'"'s telephone line.
302 Citations
29 Claims
-
1. Apparatus for transferring data over a telephone network comprising:
-
a remote data unit; and a host computer, said remote data unit and said host computer being interconnected over a telephone network; said remote data unit including; a) timing means for generating a time signal in a pseudorandom manner; b) real time clock means for generating an indication of real time; c) means for comparing said real time with said pseudorandomly generated time signal; d) means responsive to said comparison between said real time and said pseudorandomly generated time signal for accessing said telephone network when said real time bears a predetermined relationship to said pseudorandomly generated time signal; and e) means for transferring data from said remote data unit to said host computer, said transferring means further transferring a subsequently generated pseudorandom time signal generated by said timing means to said host computer; said host computer including means for receiving and comparing said subsequently generated pseudorandom time signal with a table of allowable times, said host computer further including means for sending an indication back to said remote data unit of whether the time indicated by said subsequently generated pseudorandom time signal is acceptable as shown by said comparison with said table of allowable times and, if so, said time is accepted as the next time of callback for said remote data unit and, if not, said host computer sending an indication to said remote data unit to cause said timing means to generate another pseudorandomly generated time signal, said host computer storing an indication of the acceptable time of callback for said remote data unit in said table of allowable times. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
-
-
17. A method for transferring data between a remote data unit and a host computer over a telephone network comprising the steps of:
-
(a) generating at said remote data unit a time signal in a pseudorandom manner; (b) generating at said remote data unit an indication of real time; (c) comparing said real time with said pseudorandomly generated time signal; (d) accessing said telephone network when said real time equals said pseudorandomly generated time signal; (e) transferring data from said remote data unit to said host computer; (f) transferring a subsequently generated pseudorandom time signal generated by said timing means to said host computer; (g) receiving and comparing at said host computer said subsequently generated pseudorandom time signal with a table of allowable times and sending an indication back to said remote data unit of whether the time indicated by said subsequently generated pseudorandom time signal is acceptable as shown by said comparison with said table of allowable times and, if so, accepting said time as the next time of callback for said remote data unit and, if not, said host computer sending an indication to said remote data unit to cause another pseudorandom time signal to be generated; and (h) storing at said host computer an indication of the accepted time of callback for said remote data unit in said table of allowable times. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
-
Specification