Data transmission system

• US 4,222,052 A
• Filed: 12/15/1977
• Issued: 09/09/1980
• Est. Priority Date: 12/15/1976
• Status: Expired due to Term

• Current Assignee: Ronald A. Dunn
• Original Assignee: Ronald A. Dunn
• Inventors: Dunn, Ronald A.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US05/860,675
• Time in Patent Office: 999 Days
• Field of Search: 340/505, 340/508, 340/539, 343/112 R
• US Class Current: 342/453
• CPC Class Codes: G08B 26/007 Wireless interrogation

Abstract

A computer controlled radio activated security and safety system suitable for interrogating a plurality of locations sequentially and for obtaining replies to indicate the condition of the locations and which is completely independent of any external connection between an interrogator location and an interrogatee location for interrogating a plurality of locations sequentially and obtaining replies to indicate the condition of the locations. The system comprises a computer center, at least one main transmitting and receiving station and at least one remote alarm unit which is adapted to monitor a predetermined parameter. The remote alarm unit is also provided with at least one receiver and transmitter, and the computer is adapted to interrogate the alarm unit with a predetermined digital signal and to monitor its reply, the reply being modified by any variation in the parameter.

Claims

1. A computer controlled radio activated security and safety system for interrogating a plurality of locations sequentially and obtaining replies to indicate the condition of the locations and which is completely independent of any external transmission means comprising:

a computer centre,

at least one main transmitting and main receiving station and at least one remote alarm unit independent of any transmission means associated with said main transmitting and said main receiving station and adapted to monitor a predetermined parameter,

said remote alarm unit also including at least one receiver and transmitter,

said computer centre being adapted to interrogate said alarm unit with a predetermined digital signal and on command said alarm unit will indicate normal or false conditions and to monitor its reply, the reply being modified on any variation in the parameter.

2. A system as claimed in claim 1 wherein the transmitter, receivers, and power supplies for the computer centre and base station (s) are duplicated.

3. A system as claimed in claim 2 wherein each alarm unit in a particular area has an address code other than its normal address code so that the units can be contacted at the same time so that the variation in the time of receipt of the leading edge of a burst of signal of the mobile transmitter can be coded and sent to the computer which can identify the time variations and from these triangulate the position of the mobile transmitter.

4. A system as claimed in claim 1 wherein the alarm units may be selected from the group comprised of interrogation and reply alarm units, relay interrogation and reply alarm units to act with slave alarm units, and those having an additional receiver to radio locate other units.

5. A system as claimed in claim 1 wherein the computer is adapted to repeatedly sweep a predetermined number of interrogation positions to interrogate the interrogation positions sequentially so that selected ones of the interrogation positions return a signal, which control different computer functions.

6. A system as claimed in claim 1 also having at least one spaced base station which can receive the signal from the main station and re-radiate this for reception by alarm units too distance from the main station to receive its signal.

7. A system as claimed in claim 6 wherein the signal to the base station not only includes the address of the alarm unit but also directions as to which one of a number of directional aerials should be used for the transmission.

8. A system as claimed in claim 1 wherein the computer interrogates each alarm unit by means of radio digital transmissions addressed, either by the main station or a base station, to particular alarm units and the alarm units concerned return a status signal depending on the condition of the parameter monitoring device, should the computer detect that an alarm has been raised the necessary information is displayed.

9. A system as claimed in claim 1 wherein the computer is adapted to repeatedly sweep a predetermined number of interrogation positions, slots, which control different computer functions.

10. A system as claimed in claim 9 wherein the use of slots can be selected from directing interrogation of transponders, changing channels and verifying on an alternate channel of the existence of an alarm condition or a system fault, division into a number of different alarms and the variation of necessary interrogations between day and night.

11. A system as claimed in claim 9 wherein the sweep can manually be delayed by a predetermined time.

12. A system as claimed in claim 11 wherein each alarm unit is provided with a pedestal stepping circuit the rate of stepping of which is equal to the computer sweep delay so the delay can be used to move to a different slot and thereby another channel.

13. A system as claimed in claim 12 wherein the computer is provided with means to delay the stepping of the pedestal stepping circuit to ensure the alarm units are held in synchronization with the computer.