GB2267413A - Ring detect propagator - Google Patents

Abstract

A ring detect propagator P will detect ringing signals in a telephone line or extension line L1 it is connected to or attached to. Upon ring detect the propagator will prepare to transmit its identity code via a medium such as radio waves or infra-red light. Transmission will occur when the propagator cannot detect transmissions from other propagators. Other propagators within range will receive the transmitted identity code, as will purpose-built receiver pagers. A pager will emit an audible or visual signal if a received code corresponds to its own identity code. A propagator will also transmit other propagator codes it has previously recorded. Transmissions will also be initiated when ring has not been detected but when the propagator has recorded other propagator identity codes. A propagator will not record identity codes which are already recorded within it, nor will it record identity codes which it has recently transmitted. <IMAGE>

Description

RING DETECT PROPAGATOR This invention relates to a ring detect propagator.

Extension telephone systems are well known; they are to be found throughout the commercial, business and administrative worlds.

The vast majority of these systems suffer from a well known shortcoming in that while individual extension telephones are usually fixed to a location, the people who answer them are not.

The degree to which this is a problem depends upon the frequency of changes of location that personnel need to make, and the degree of importance attached to contacting them at the time of calling.

Paging systems which attempt to address this problem already exist, examples include: PA systems; localised radio systems with centralised transmitters and where individuals carry radio-receiver pagers, and similar systems with networks of centralised transmitters used on a national scale.

However, these paging systems all suffer from various handicaps which prevent them from being widely practical solutions: PA systems are highly intrusive and are, accordingly, unsuitable for many situations; private radio paging systems with centralised transmitters are expensive to install; nationwide radio paging systems are intended for long distance use and are impractical for "in house" use, they incur rental charges in addition to the initial high purchase cost of pagers; radio paging systems generally require operating licencing and hence administrative burdens at some level. Finally, most systems employ a centralised 'control' mechanism whereby the centralised control must first be contacted and given the identity or identifying label of the individual or extension to be paged.

The invention described herein is the nodal element which will form the basis for a practical, low-cost, networked, paging system which: is non-intrusive; has a cost function related to the number of extensions covered; does not incur rental charges; does not incur high installation costs or efforts; does not require a centralised control mechanism; does not require operating licencing; does not incur administrative burdens; is useful to a wide range of commercial, business, and administrative concerns.

According to the present invention there is provided a ring detect propagator comprising a telephone line ring detector, a receiver, a transmitter, means to decode received signals into internal codes, means to encode internal codes into signals suitable for transmission, means for recoding codes, means for accessing recorded codes, means for comparing recorded codes with incoming codes, means for comparing a preset identity code with recorded and incoming codes, means to erase all or selected recorded codes, means of timing the recordings of codes and transmissions of codes.

Specific embodiments of the invention will now be described by way of examples, with reference to the accompanying drawings in which: Figure 1 shows the basic operation without propagation; Figure 2 shows simple propagation.

BASIC OPERATION Referring to Figure 1, "Basic Operation - No Propagation", a ring detect propagator (P) is preset with the number of the PABX extension it is to be connected to. It is then plugged into the PABX extension socket (S) and the extension telephone line (L2) is plugged into the propagator (the propagator does not interfere with the normal operation of either the PABX or the extension telephone).

A purpose-built, receiver-pager (R-P) is preset to the number of this extension: the receiver-pager is carried by an individual (for example, it can be worn as a lapel badge).

When the extension is called the propagator detects ring (from the line signal) and it transmits its own identity code, the matching receiver-pager decodes this signal and recognises it as its own code it emits an audible warning to alert the individual carrying it that the extension telephone is ringing.

SIMPLE PROPAGATION Referring to Figure 2, "Simple Propagation", a receiver-pager (R-P) is out of range of the initiating propagator's (P1) transmission CR1).

The initiating propagator is plugged into extension line (L1). A second propagator (P2) which is within range, and which is plugged into a different extension line (L2), receives this code and records it. This second propagator then waits for a randomised (pseudo-random) period of time before attempting to re-transmit this code. It will transmit only when it cannot detect transmissions from other propagators.

The receiver-pager (R-P) is within the range (R2) of this second propagator and it recognises the code as it own - as in the first case it then emits an audible warning.

This simple propagation continues throughout the network of propagators.

TRANSMISSION DELAY AND QUIET STATE When a propagator has detected ring or a transmission from another propagator it waits for a randomised (pseudo-random) period of time before transmitting. If it detects transmissions from another propagator during this waiting time it will abandon its waiting state and begin receiving the transmission. Once the transmission is finished it will once again wait for another randomised period of time before it begins transmitting; it will not transmit until the medium is in a quiet state. This process will be continued until it successfully transmits.

The randomised transmission delay ensures that there is a high probability that transmission clashes will be reduced in cases where two or more propagators receive the same transmission simultaneously: the randomised delay creates a high chance that one propagator will begin transmitting before another.

PROPAGATION CONTROL Unwanted re-cycling of codes back and forth throughout the network is prevented by the following means: a propagator will record a code it has transmitted in a list of 'transmitted' codes. If this code is subsequently received by the propagator while it exists in the 'transmitted' list the code will not be recorded in a 'to be transmitted' list, and hence it will not be re-transmitted.

After a specified period of time, which allows the code to reach all propagators in the network, and which is typically less than the time between ring pulses, the propagator will erase its recoding of the 'transmitted' code; it will thus be ready to propagate the next transmission of this particular code - which will originate from the propagator which detects ring, rather than from a re-cycling of a propagated code. Propagation is thus 'outward' throughout the network of propagators.

MULTIPLE CODE TRANSMISSIONS During the time a propagator is waiting to transmit it will receive and record incoming codes. A list of codes 'to be transmitted' will thus be formed. Each incoming code is compared against this list and is recorded only if does not already exist in the list (and if it does not exist in the 'transmitted' list); thus duplications will not occur.

Once the 'to be transmitted' list has been transmitted the recorded codes are erased and re-recorded in the 'transmitted' list.

COLLISIONS AND CORRUPTED CODES When a propagator has received overlapping transmissions from other propagators each of which is out of the range of the other, and each of which correctly tested for a 'no other transmissions' state before transmitting, the propagator will not record any codes but, instead, will transmit a 'request for re-transmission'. Propagators receiving such a request will re-transmit the batch of codes most recently listed in the 'transmitted' list. Similarly, propagators which detect corrupted signals will transmit a 'request for re-transmission' signal.

LINE POWER A propagator will draw its operating power from the line it is connected or attached to. In cases where there is insufficient power available from the line, provision is made for operating power to be drawn from an alternative power source, such as a battery.

DISPLAYS AND INTERNAL STATES A propagator may be optionally equipped with 'state' indicators which show whether it is: idle; waiting to transmit; receiving; or transmitting. A propagator may also be equipped with an optional display which shows its own identity code, or the last code received or transmitted depending upon the state of the propagator.

NETWORK DISCRIMINATION A code will also contain a preset network identity component so that networks which are separate, but which overlap each other's range, do not interfere with one another. This component will be preset at manufacturer or agent level; it will be on-site adjustable.

Claims (16)

1 A ring detect propagator comprising a telephone line ring detector, a receiver, a transmitter, means to decode received signals into internal codes, means to encode internal codes into signals suitable for transmission, means for recoding codes, means for accessing recorded codes, means for comparing recorded codes with incoming codes, means for comparing a preset identity code with recorded and incoming codes, means to erase all or selected recorded codes, means of timing the recordings of codes and transmissions of codes.

2 A ring detect propagator as claimed in Claim 1, wherein the ring detector has the means to detect signals transmitted along lines or wires where the purpose of the signals is to indicate to devices attached to the lines or wires, such as telephones, that they are being called.

3 A ring detect propagator as claimed in any preceding Claim, wherein a transmission medium includes radio waves or infra-red light or other electromagnetic waves or sound waves.

4 A ring detect propagator as claimed in any preceding Claim, wherein it is provided with means to detect when the transmission medium is in a quiet state suitable for transmission.

5 A ring detect propagator as claimed in any preceding Claim, wherein means is provided to set or enter or alter its identity code.

6 A ring detect propagator as claimed in any preceding Claim, wherein the propagator is powered solely or partially from the line or wire it is connected or attached to.

7 A ring detect propagator as claimed in any preceding Claim, wherein the propagator is powered solely or partially fre an internal or external power source.

8 A ring detect propagator as claimed in any preceding Claims, wherein means is provided to prevent transmission of any or selected codes when timing periods have elapsed.

9 A ring detect propagator as claimed in any preceding Claim, wherein means is provided to display or show a recorded, received, or preset code.

10 A ring detect propagator as claimed in any preceding Claim, wherein means is provided to display or indicate the internal states of operation of the propagator.

11 A ring detect propagator as claimed in any preceding Claim, wherein means is provided for the propagator to be plugged into telephone line or telephone extension line sockets or outlets.

12 A ring detect propagator as claimed in any preceding Claim, wherein means is provided for telephone lines or telephone extension lines to be plugged into it.

13 A ring detect propagator as claimed in any preceding Claim, wherein it is provided with means to identify when incoming signals have been corrupted.

14 A ring detect propagator as claimed in any preceding Claim, wherein it is provided with means to transmit requests for retransmission to other propagators.

15 A ring detect propagator as claimed in any preceding Claim, wherein means is provided to discriminate one network of propagators from another.

16 A ring detect propagator substantially as described herein with reference to Figures 1-2 of the accompanying drawings.