New Technology
The new technology utilised in the "No New Wiring" Alarm System enables the alarm signals
to be successfully transmitted through a standard 120 volt 60 Hz electrical distribution
system. This is the electrical system found today in most homes and commercial buildings
in North America.
The key to the success of this technology is that it offers the following features:
For the more technologically-minded, "click here" to go to a further explanation of the
simultaneously without interfering with each other.
above features.
The main components of the "No New Wiring" Alarm System are the Transmitter
and Receiver modules. These are low cost items designed for easy installation and
supplied in plug-in or hard-wired versions.
A Transmitter module is used at one location to transmit a coded signal through the
existing AC power wiring to a Receiver unit(s). The Receiver would receive, decode and
act on the signal. It might express an "alert" to the alarm condition and/or initiate some
further action such as a buzzer, strobe light, siren or auto-dialer.
In this alarm system, no new wiring is required.
Transmitters
The Transmitter modules connect directly to the AC power wiring either by plugging into a
standard power outlet or by hard-wiring. Each contains a DIP switch for setting a location
code.
The hard-wire units are miniaturized for concealment in the electrical outlet box, behind
a detector or other appliance. Simple fitting instructions are supplied with each module.
Transmitters are available for a wide variety of applications. They can be triggered by almost
any type of detector or manually (see Uses). When triggered, they transmit a coded signal
which is defined by the chosen DIP switch setting. Each Transmitter can be readily identified
and located from its DIP switch setting.
The alarm system can easily be expanded by adding any number of Transmitters. Each one
can be DIP coded to transmit only to specific Receivers without interference from any
of the other units.
Receivers
Receivers are available for both plug-in and hard-wire installation. The hard-wire units are
miniaturized for concealment in the electrical outlet box, behind a light, horn or other
appliance. Simple fitting instructions are supplied with each module.
All Receivers are single channel units in that they only respond to the Transmitter(s) whose
DIP switch setting matches their own. All other Transmitters are ignored so that the precise
location(s) of matching "live" Transmitter(s) can quickly be identified.
Receiver modules are available for a wide variety of functions: When activated by a signal
from a "matched" Transmitter, they can be used to set off an audible buzzer, strobe light,
auto dialer or other appliance. For some suggested applications go to Uses.
All Receivers are "non-latching" units. This means that once the Transmitter signal is
received, the Receiver will operate until the Transmitter stops signalling whereupon the
Receiver will automatically reset after 5 seconds.
Monitor and Display Panels
Various models of Monitor and Display Panels are available. The purpose of these is to
respond to signals from Transmitters and display their location code(s) (i.e. DIP switch setting).
The Panels contain an alarm buzzer, a relay to supply an electrical output and an indicator
light to announce each Transmitter's location(s).
These Panels are all "latching" units. Once a Transmitter's signal is received, they latch
into an alarm mode whereupon a buzzer is set off, a relay is activated to provide an electrical
output and a light comes on to indicate the transmitter location. This all continues until
the Panel has manually been reset after the Transmitter had stopped signalling.
To ensure reliable operation, the Monitor and Display Panels react to Multiple Code Word
commands. This means that they do not respond unless or until they receive at least two
consecutive code words from the same Transmitter within a 5 second time interval.
There should thus be no false alarms due to noise or intransients.
Extending a "No New Wiring" Alarm System
A big advantage of the "No New Wiring" Alarm System is that it can easily be extended
from one location to cover other areas on the same electrical power distribution system.
This is because the Transmitter and Receiver modules can communicate signals from
any point on the AC Power system that is served by the same Transformer.
In residential areas, electrical power is normally on a single phase system and distributed
to 8-10 houses which all share the same Transformer. "No New Wiring" Transmitter and
Receiver modules can not only be used within each of these houses but also between
them to provide greater alarm system coverage.
For example, if the Jones family were going on holiday, they would first plug-in some Transmitter modules to alarm their home for security.
They would have also pre-arranged with their neighbours, the Smiths (whose home is on the same power Transformer) to plug-in a Receiver module in their home.
Whilst away, if any Transmitter were activated in the Jone's home by say an intruder break-in, the coded alarm signal would immediately transmit through the existing power lines into the Smith's home and set off the Receiver.
In fact all the neighbours (whose home power shared a Transformer) could plug-in any number of "No New Wiring" modules to set up an extensive "Neighbourhood Watch" Security System.
Similarly, "No New Wiring" alarm systems can be set up to cover the safety and security of apartment buildings, condominiums, retirement homes, hospitals, schools . . .etc., with modules plugged-in to transmit and receive coded alarm signals throughout the existing AC power wiring of each location or between locations on the same electrical power distribution system.
Commercial, Industrial and Institutional Buildings and Facilities usually have a 3-Phase Power Distribution System. All Transmitter and Receivers will operate normally if plugged into any of the outlets on the same phase. However, if all outlets throughout the building are to be used in the alarm system, then a 3-Phase Coupler-Repeater Unit must be installed to allow the alarm signal transmission across the wiring of all phases.
Some Residential uses
Some Commercial uses
Signal Boosters and Couplers
Signal Boosters and Couplers may be necessary to insure integrity throughout the system. 
Signal Boosters are used to compensate for signal loss due to long distances and/or heavy
current loads. This may be the case for large buildings such as factories, high-rise office
towers, hospitals. . . etc.. Also, homes in rural locations sharing the same transformer may
need some help to overcome the extra distance in power lines. Easy Plug-in or hard-wire
Signal Booster modules are available and normally solve the problem. If you think distance
might be an issue for your "No New Wiring" Alarm System, you should first try out a set of
Transmitter and Receiver modules to see if they work.
For 3-phase installations as found in most factories, a 3-Phase Coupler should be used.
And in locations, where there are multiple transformers such as large buildings, a
Transformer Coupler should be installed. Both units are modest in price and easy to install.
About The Technology
(Extracts from a recent paper written by the Inventor)
"No New Wiring" Technology; involving the transmission of
signals over the existing AC Powerlines, has held a lot of
promise for Security, Event Monitoring, Remote Control, and
Energy Management applications. This technology uses the
existing AC Power wiring for the transmission of control, status,
or emergency type signals from point-to-point within a building,
or from one building to another (as long as they share a common
utility transformer), without the expense and inconvenience of
adding new wires.
The use of powerlines for signal transmission have been limited
in their applications because of the large amounts of electrical noise
and transients found on the powerlines, particularly in commercial
and industrial applications, where a 3-phase power distribution system
is used.
"No New Wiring" Technology offers unique solutions to these
problems using Zero Crossing Digital Pulse Modulation and
Consecutive Pulse count Coding technologies, that are
covered by United States, British, and Canadian Patents, with
other patents pending.
The key to the success of this technology is in the fact that it
allows for the economical inclusion of such features as:
Noise Detection and Evasion
Time Division Multiplexing
Multiple Code Word Commands
3-Phase power system distribution system operation
(Industrial and Commercial Applications)
These features are all combined in our, "No New Wiring System"
to make them every bit as reliable as direct wire systems,
with the added advantages of being more flexible, and
much less costly.
Zero Crossing Digital Pulse Modulation
In the Zero Crossing Digital Pulse Modulation process, the
AC Powerline is modulated by placing a high level pulse at the
zero crossing of the AC wave, forming a 120 pulse per second
pulse train. The amplitude of these pulses is in the order of 100
volts for 120 vac operation. This modulation process offers the
following features that are important to reliable system operation.
First, the signal pulses are, for the most part, isolated from the
AC Powerline noise and transients since these are not normally
present at the zero crossings.
Second, the large amplitude of the modulating pulses insure that
the signal is not masked by the AC Powerline noise and
transients.
Third, since the zero crossing is a stable and well defined point
on the AC wave, it allows system synchronization to facilitate
such features as Noise Detection and Evasion and Automatic
Multiplexing for the simultaneous operation of multiple
Transmitters without interference.
Consecutive Pulse Count Coding
In the Consecutive Pulse Count Coding technique, the code
information is contained in the number of consecutive pulses
transmitted before a "missing pulse". By missing pulse we mean a
zero crossing on the AC wave that does not contain a pulse. For
example, 40 consecutive pulses might be code #1, and 41
consecutive pulses might be code #2. Then to transmit code #1
followed by code #2, a modulation pulse would be placed at 40
consecutive zero crossings (code #1), and then at least one zero
crossing would be skipped (missing pulse), and then a
modulation pulse would be placed at 41 consecutive zero
crossings (code #2).
From this we see that each code is a pulse train with a precise
number of consecutive pulses. This means that increasing or
decreasing the length of the pulse train is the only way to alter the
code. To increase the length of the pulse train, pulses must be
added to either the beginning or end of the pulse train, and to
decrease the number of pulses in the pulse, one or more of the
existing pulses would have to be eliminated.
At the Receiver, a zero crossing "gate" and level detector are
used to reject all pulses that are not at the zero crossing or of
sufficient amplitude. As far as the Receiver is concerned, a pulse
is any perturbation of either polarity (plus or minus) that exceeds
the threshold. When you consider the amplitude of the signal
pulses is on the order of 100 volts, with several peaks caused by
the "ringing" on the AC Powerline, the likelihood of a pulse being
cancelled by noise or transients is nonexistent.
In summary then, the key features of the Consecutive Pulse
Count Coding are that each code is of a different length, that is,
contains a different number of pulses. The code is altered only by
the addition of one or more pulses at the beginning or end of the
pulse train. Noise or transients that occur in the middle of the
pulse train have no effect on the code.
Transmitter Operation
In order to insure that no pulses are added to the beginning of its
code, each transmitter continuously monitors the AC Powerline
with the same zero crossing gate circuitry that is contained in the
Receivers. When it detects a pulse at the zero crossing, it
generates a "busy" signal that inhibits the start of its transmission.
This means that the transmitter will delay (in increments of 8.33
milliseconds) its transmission until it detects a zero crossing that
contains no pulse, thereby insuring that no extra pulse is added to
the start of its code. In this way it is able to evade noise or
transients, or pulses from other transmitters, that have the
potential of adding pulses to the start of its own code. In
addition, this feature allows multiple transmitters to avoid
interfering with each other. This leaves only the possibility that
the code can be altered by the addition of one or more pulses to
the end of the pulse train. In order to eliminate the possibility of
having a Receiver interpret a pulse added to the pulse train as a
valid command, Multiple Code Word Commands are used.
Multiple Code Word Commands
Multiple Code Word Commands means that the receiver is
required to receive at least two (2) identical code words within a
one second period before it interprets that code word as a valid
command.
To show how extremely effective this requirement is in reducing
false commands, consider the following example. Assume that
the electrical powerline on which we are operating is so noisy
that with a single code word command, we can expect one false
command to occur each day (24-hour period). From probability
theory, we can the calculate the expected false command rate
when we require each command to contain two identical code
words within a one-second interval.
There are 86,400 one-second intervals in one day (24 hours).
From the theory of probability, the probability of two false code
words occurring in a one-second interval is:
This shows that as a result of requiring two identical code words
in a one second period, we went from a false command rate of
one per day, which could not be tolerated, to a false command
rate of one in over 237 years.
Time Division Multiplexing
The coding technique and transmitter operation described above
allows multiple transmitters to automatically synchronize
themselves and to avoid interference from AC Powerline noise
and transients, and from each other. As described previously,
each transmitter will delay its transmission until it detects a
missing pulse, thereby insuring that no other transmitter is
signaling. This amounts to Automatic Time Division
Multiplexing, which allows each transmitter to transmit in a
separate time slot without interference from other transmitters.
Operation On a 3-Phase Power Distribution System
Commercial facilities (factories, institutions, hospitals, office
buildings, hotels/motels, etc.) almost always have 3-phase power
distribution systems (120V/208V). In a 3-phase power
distribution system the times at which the zero crossing occur is
different from phase-to-phase. The figure below shows the
voltage waveshapes of a 3-phase power distribution system.
Note that the point at which the voltage wave crosses zero
occurs 120 degrees later on the 2nd phase than on the 1st
phase, and 240 degrees later on the 3rd phase. From our
discussions on powerline carrier reliability, one of the keys to
reliable operation was the placement of the signal pulses at the
zero crossings.
The 3 Phase Coupler/Repeater, Model XXXX, is used to
accomplish this when operating on a 3-phase system. Referring
again to the 3-phase waveshapes, when the Transmitter is on the
1st phase, it places its pulses at the zero crossings of that phase,
and the 3 Phase Coupler/Repeater will repeat the exact pulse
count at the zero crossings of the other two phases (with the
appropriate delay).
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