Telephonic information communication method and apparatus

An apparatus for communicating information between customer locations and remote locations desiring the information exchange which allows the communications to occur over existing communications lines without interfering with the existing uses of those lines. The apparatus includes an acquisition device located at the customer's location, and a signal shifting means located at a local distribution point in relatively close proximity to the customer's location which receives an out-of-band signal from the customer location and converts it to an in-band signal transmitted over the greater distance to the remote location desiring the information exchange using normal telephone transmission through telephone company switch equipment. Also disclosed are methods for customer information exchange, in particular utility meter information, over existing communication lines, in particular telephone lines wherein the signals are transmitted out of band to a local distribution point then retransmitted to in-band signals for further transmission.

FIELD OF THE INVENTION 
This invention relates to methods and apparatus for communicating 
information between customer locations and remote locations desiring the 
information exchange. More particularly, the present invention is directed 
to such methods and apparatus which allow the communications to occur over 
existing communications lines without interfering with the existing uses 
of those lines. 
BACKGROUND OF THE INVENTION 
Various systems for utilizing existing telephone lines and power lines for 
carrying data from numerous locations for collection at a remote location 
point are known. Such systems are economically advantageous as they are 
able to utilize the existing infrastructure of these transmission media 
which extends to a significant portion of all the residential and business 
locations in the United States. However, the utility of the previously 
proposed systems is limited by the conflicting use of the lines for the 
existing purposes such as voice communications for the telephone network. 
Therefore, previous low cost systems have failed to provide the capacity 
to do demanding real time applications which cannot operate effectively 
using normal dial up procedures. An example of such a real time 
application is demand recording from utility meters. An additional problem 
with such previously known systems in real time applications is that the 
existing line must be released on demand for the existing use. For 
example, when the customer picks up his telephone to place a call the line 
must be made available to the customer. The present invention overcomes 
these limitations by utilizing the beneficial aspects of existing 
communications lines and telephone access while allowing access to the 
customer's location in a manner which does not affect existing uses for 
the existing communications line. 
The present invention takes advantage of the structure of existing 
telephone lines. Existing lines are designed to preferentially pass only 
signals in the 300-3500 Hz frequency range which are audible on 
conventional telephone instruments. Existing telephone lines are run from 
the central office switch to a local distribution point known as a 
telephone company interface box (also referred to as a telephone pedestal 
or telephone vault) within which each individual pair is connected to the 
two-wire "loop" to the subscriber's house. A number of telephone lines fan 
out from the telephone company interface box to individual residences in a 
given neighborhood. The telephone interface box is typically within two 
thousand feet of each of the residences it serves, and within a few 
hundred feet in a great many cases. In every case, however, it lies 
between the residence and the telephone switch through which conventional 
calls must pass on their way to or from the residence. The telephone 
interface box typically has no power supply as the phone system works on 
power supplied by batteries associated with the switch. 
The central office switch is an elaborate and expensive computerized device 
which permits any telephone on the system to be connected to any other. 
There is a separate, identifiable pathway from each numbered connection on 
the switch to a corresponding subscriber's telephone. From the 10,000 
numbered connections on a typical switch, large bundles ("trunks") of 
individual lines disperse to the various neighborhoods served, each line 
("pair") destined for a given subscriber's instrument. In each 
neighborhood the individual pairs in a trunk then enter a telephone 
company interface box. 
The present invention utilizes the switched phone network to interface with 
an apparatus located at the telephone company interface box or other local 
distribution point to allow large numbers of customer locations to be 
rapidly accessed without the burdensome overhead of the switch while still 
maintaining the low cost benefits of the existing phone network. The 
present invention also provides for information access without 
interference with existing communication uses by utilizing normally 
attenuated out-of-band frequencies for communications over the relatively 
short distances between the local distribution point and the customer 
locations. The present invention further permits information access while 
telephone service is disconnected (cut-off at the switch). The present 
invention also avoids the problems which frequent telephone number 
reassignments cause previous systems which require a telephone call to be 
placed to each customer location. 
To provide an economically feasible apparatus for communicating information 
between individual residential or commercial locations and remote 
locations it is an object of the present invention to take advantage of 
the infrastructure of existing communication lines such as telephone lines 
or cable lines. Furthermore, to allow such a system to operate in a real 
time or on demand mode, it is an object of the present invention to 
provide an apparatus which is designed to operate independently of the 
existing uses for the line to allow simultaneous use of the existing 
communication lines for their present purpose as well as for either 
bidirectional or unidirectional information exchange. 
It is an object of the present invention to provide an apparatus for 
automated acquisition of one or more of a customer's utility meter 
readings using the customer's telephone line. 
It is a further object of the present invention to provide an apparatus 
which may be used to collect readings from one or more meters or other 
devices at one or more customer locations. 
It is a further object of the present invention to provide a method for 
customer information communication between a customer and a requesting 
location over existing communication lines. 
It is a further object of the present invention to provide a method for 
communication of customer information even while voice service is 
disconnected. 
It is a further object of the present invention to provide a method of 
reducing the cost of maintaining a data communications link with a given 
location even though the telephone number of that location may be 
frequently changed. 
It is a further object of the present invention to provide a method for 
automated utility meter reading over a telephone line of a customer 
regardless of whether a request is received from a remote location. 
SUMMARY OF THE INVENTION 
These and other objects are provided by the apparatus of the present 
invention which includes an acquisition means electrically connected to 
the customer's telephone line which converts the customer's utility meter 
readings or other information to an out-of-band electrical signal. The 
acquisition means transmits the out-of-band electrical signal over the 
customer's telephone line at a frequency sufficiently offset from customer 
voice communication frequencies to substantially reduce interference 
during concurrent transmission of both the out-of-band electrical signal 
and customer voice communications over the customer's telephone lines if 
such voice communications are underway or initiated. The apparatus further 
includes a signal shifting means located at a local distribution point 
which converts the out-of-band electrical signal from the customer's 
telephone line to an in-band electrical signal. The in-band electrical 
signal is configured to be transmitted over a telephone link connecting 
through a telephone company central office switch to a remote location. 
This apparatus provides the customer's utility meter readings to the 
remote location automatically. 
In another aspect of the invention an apparatus is provided wherein each 
signal shifting means is adapted to obtain information from a plurality of 
customers whose telephone lines connect through the local distribution 
point where the signal shifting means is located. The remote location may 
acquire information from numerous local distribution points by placing 
calls to signal shifting means located in each local distribution point. 
In one such embodiment the signal shifting means includes a scanning means 
located at each local distribution point which receives the out-of-band 
electrical signal from each of the customers' telephone lines without 
disrupting customer voice communications. The scanning means has a 
plurality of input ports and an output port. The input ports are 
electrically connected to the customers' telephone lines and the scanning 
means selectively provides a selected meter reading at the output port. 
The signal shifting means also includes a control means electrically 
connected to the scanning means which selects the meter readings to be 
provided at the output port of the scanning means and selectively groups 
one or more of the selected meter readings from the scanning means as a 
data reading packet, The signal shifting means also includes a 
re-transmitting means electrically connected to a telephone link 
connecting through a telephone company central office switch. The 
re-transmitting means is responsive to the control means and transmits the 
data reading packet as an in-band electrical signal over the telephone 
link. A communication means located at a remote location receives the 
in-band electrical signal over the telephone link. 
In another aspect of the invention a method is provided for customer 
information communication. A request for customer information from a 
requesting location is transmitted by telephone through a telephone 
company switch to a local distribution point. The request is received at 
the local distribution point. A request for customer information is 
transmitted from the local distribution point to the customer over 
existing communication lines modulated at a first out-of-band frequency 
range as an out-of-band frequency request. The out-of-band frequency 
request from the local distribution point is received at the customer 
location to provide an information request to the customer. Customer 
information responsive to the information request to the customer is 
electrically encoded and transmitted over the existing communications 
lines modulated at a second out-of-band frequency range as an out-of-band 
frequency information reading. This information reading is received at the 
local distribution point and re-transmitted from the local distribution 
point at in-band-frequencies through a telephone company switch to the 
requesting location. It is a further object of the present invention to 
provide a method as described suitable also for customer control 
communication between a customer and a requesting location over existing 
communication lines where there may or may not be any need to transmit 
information from the customer location back to the remote location. 
As a further aspect of the invention, a method is provided for automated 
utility meter reading. One or more of a customer's utility meter readings 
are electrically encoded. The electrically encoded readings are 
transmitted onto the customer's telephone line as an out-of-band frequency 
reading signal which is operatively transmitted concurrently over the 
customer's telephone line between the customer and the local distribution 
point with or without any customer voice communications. The encoding and 
transmitting steps are performed one or more times. Selected ones of the 
out-of-band frequency readings are received at a local distribution point. 
They are converted to data readings at the local distribution point. The 
data readings are selectively re-transmitted as in-band frequency reading 
signals over a telephone link connecting through a telephone company 
central office switch and then acquired at one or more remote locations 
through the telephone company central office switch to provide the 
customer's utility meter readings automatically to the remote locations. 
It is a further object to provide such a method suitable for reading one 
or more types of utility meters of a plurality of customers using the 
customers' telephone lines by grouping the data readings from selected 
customers to provide a data reading packet which is selectively provided 
and acquired at the appropriate remote location.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention will now be described more fully hereinafter. This 
invention may, however, be embodied in many different forms and should not 
be construed as limited to the embodiments set forth herein; rather, these 
embodiments are provided so that this disclosure will be thorough and 
complete, and will fully convey the scope of the invention to those 
skilled in the art. 
An embodiment of the information communication apparatus of the present 
invention is generally shown in FIG. 1. In this embodiment, customer 
information, such as utility meter readings and alarm conditions, is 
transmitted from a customer location to the requesting location without 
any communication from the requesting location back to the customer 
location. The meter reading or other customer information is converted by 
modulator 10, which is located at the customer location, to an out-of-band 
signal that will not interfere with the existing communication line usage. 
However, as the existing communication line is specifically designed to 
attenuate such out-of-band signals, such a signal is not able to be 
transmitted over long distances. Therefore, the signal is received at an 
intermediate location where it is converted back into a data format by 
demodulator 12. The customer information is then converted by modem 14 
into an in-band-frequency signal suitable for normal transmission over the 
existing communication line. Consequently, the signal is only carried 
transparently on a shared line to the intermediate location after which it 
is transmitted on its own line with bi-directional communications between 
modem 14 and the requesting location. 
Alternatively, as shown in FIG. 2, bi-directional communications to the 
customer location may be provided. Bi-directional communications are 
obtained by the addition of a second demodulator 16 at the customer 
location and a corresponding second modulator 18 at the intermediate 
location. If second modulator 18 and second demodulator 16 are designed to 
operate at a different carrier frequency from modulator 10 and demodulator 
12, information communication in both directions may occur simultaneously 
over the existing communication line. Such a bi-directional arrangement 
allows reading of demand recorders, remote service disconnect with 
confirmation, provides a domestic automation gateway and provides greater 
selectivity in meter reading applications. 
An embodiment of the apparatus of the present invention for automated 
reading of one or more utility meters of each of a plurality of customers 
using the customers' telephone lines is shown in FIG. 3. Acquisition means 
20 located at the customer's residence is electrically connected to the 
customer's telephone line 22 and also to one or more of the customer's 
utility meters 24 providing utility meter readings. The apparatus may also 
be connected to other information sources/control devices 26 at the 
customer location. Acquisition means 20 converts the utility meter 
readings to an out-of-band electrical signal and transmits the out-of-band 
electrical signal over the customer's telephone line 22. Acquisition means 
20 includes an encoding means 30 operatively associated with one or more 
of each of the customers' utility meters 24 or other information sources 
or control devices 26 for converting the customers' utility meter readings 
to an electrical signal, and a transmitting means 32 electrically 
connecting encoding means 30 to the customer's telephone line and 
converting the electrical signal to an out-of-band electrical signal. The 
out-of-band electrical signal has a carrier frequency selected so as not 
to interfere with the customer's normal voice communications over 
telephone line 22. This is accomplished in this embodiment using the 
existing customer's telephone line by having the frequency of the 
out-of-band electrical signal sufficiently offset from customer voice 
communication frequencies to substantially reduce interference during 
concurrent transmission of both the out-of-band electrical signal and 
customer voice communications over the customer's telephone lines. In one 
embodiment using telephone lines for transmission, the frequency of the 
out-of-band electrical signal is between about 20 kHz and about 100 kHz. 
As shown in FIG. 4, transmitting means 32 is a meter interface unit located 
in a socket extender behind the watthour meter, and draws its operating 
power from the electric utility's side of the meter. Meter interface unit 
32 includes several components: a power supply of conventional design such 
as the Polytron P33-12SXE; a modulator such as Exar's XR-2206P integrated 
circuit and related components; and a microcontroller such as the Hitachi 
H8-300. Transmitting means 32 may also include various components 
providing protection against noise, lightning and other surges. The meter 
interface unit 32 obtains its meter-reading inputs from a dial encoder 30 
or other encoding means. One suitable type of encoding means for utility 
meters is the Cain Encoder.TM., which is described in U.S. Pat. No. 
4,007,454, the disclosure of which is incorporated herein by reference as 
if set out in its entirety. 
Meter interface unit 32 serves to power encoding means 30, obtain dial 
readings from it, convert these dial readings to inaudible signals, and 
place these signals on the customer's line at the protector or other point 
slightly "upstream" (i.e., toward the telephone pedestal) from the 
customer's telephone instrument such as to be detectable by signal 
shifting means 34. Meter interface unit 32 is capacitively coupled to line 
22, therefore the customer's use of line 22 is not affected, and because 
the data stream is at out-of-band frequencies (in one embodiment, 20 and 
22 kHz) it is inaudible when line 22 is in use. Moreover, for the same 
reason the data stream cannot interfere with facsimile machines, modems, 
or answering machines, all of which use only in-band signals. 
Signal shifting means 34 located at a local distribution point, such as a 
telephone company interface box (also referred to as a telephone pedestal 
or vault) or CATV amplifier (where used with the cable line as the 
existing communication line rather than the telephone line), converts the 
out-of-band electrical signal from the customer's telephone line 22 to an 
in-band electrical signal having a frequency within the range of customer 
voice communications. The in-band electrical signal is configured to be 
transmitted over a second telephone link 36 connecting through a telephone 
company central office switch 38 to a remote location 40. A connection is 
made using normal voice frequency in-band communications connected through 
the telephone company central office switch between remote location 40 and 
signal shifting means 34. Once the connection is made, the customer's 
utility meter readings may be provided to remote location 40 either 
responsive to a request from remote location 40 or initiated by the signal 
shifting means 34. 
As shown in FIG. 4, one embodiment of signal shifting means 34 includes 
scanning means 50, control means 52 and re-transmitting means 54, all of 
which are located at the local distribution point. Scanning means 50 
receives the out-of-band electrical signal from each of one or more 
customer's telephone lines 22 without disrupting customer voice 
communications. Scanning means 50 has a plurality of input ports 60 and an 
output port 62. Input ports 60 are electrically connected to the 
customers' telephone lines 22. Scanning means 50 selectively provides 
selected meter readings from acquisition means 20 associated with 
different customers received at respective ones of the input ports 60 at 
output port 62. 
Control means 52, which is electrically connected to scanning means 50, 
selects the meter reading to be provided at output port 62 of scanning 
means 50. Control means 52 also selectively groups one or more of the 
selected meter readings from scanning means 50 into a data reading packet. 
In one embodiment, the data reading packet would include the most recent 
meter readings from a particular meter type, such as a gas meter, for all 
of the plurality of customer locations whose telephone lines 22 are 
electrically connected to the input ports 60 of scanning means 50. 
Re-transmitting means 54, which is electrically connected to a second 
telephone link 36 connecting through telephone company central office 
switch 38, transmits the data reading packet as an in-band electrical 
signal over telephone link 36. Re-transmitting means 54 operates 
responsive to commands from control means 52. 
Communication means 70, which is located at the remote location 40, 
receives the in-band electrical signal from re-transmitting means 54 over 
telephone link 36. In one embodiment of the present invention, 
transmission of the data reading packet is initiated responsive to a 
request from remote location 40 which is transmitted to signal shifting 
means 34 by communication means 70. In such an embodiment, communication 
means 70 includes a command means 72 which provides a data request which 
is transmitted by communication means 70 over telephone link 36. On 
receipt of the request, control means 52 provides an updated data reading 
packet and initiates transmission of the data reading packet by 
re-transmitting means 54. The data request from the remote location may 
also instruct control means 52 as to what information to include in the 
data reading packet. 
An embodiment of the signal shifting means 34 of the present invention is 
shown in FIG. 5. Signal shifting means 34 includes a ring-detect circuit 
100 of conventional construction such as AT&T's LB1006AB integrated 
circuit which is electrically connected to telephone link 36. A relay 102 
such as a Potter & Brumfield T83S11D132-05 connects signal shifting means 
34 to telephone link 36. Power supply 104 for regulating power to signal 
shifting means 34 consists of a DC-to-DC converter such as a Datel 
UWR-5/500-D48 and related components. Comparator 106, such as the Maxim 
MAX480CPA serves as a low voltage detector for use with the power control 
logic of signal shifting means 34 to be described. Control means 52 
includes microcontroller 108 which provides logical functions. 
Microcontroller 108 may be a Hitachi H8-300 or similar microcontroller. 
Scanning means 50 includes a group of individually controllable DPST 
switches 116 such as AT&T's LH1503AB solid-state relays. Switches 116 are 
connected to respective ones of the customer's telephone lines 22, 22'. 
Each of the customer's telephone lines 22, 22' is also connected through, 
either on a dedicated line or through an SLC not shown in the Figure, to 
the telephone company switch 38 used for the customer's normal telephone 
communications. Activation of any such switch 116 causes modem 54 or other 
re-transmitting means to be capacitively coupled to each of the two 
conductors, the tip and ring lines, which comprise the corresponding line 
22. This capacitive coupling does not permit DC current to flow from the 
customer's telephone line 22 through signal shifting means 34. If such a 
current were to flow, the telephone company central office switch 38 would 
think the customer wished to make a call and would take respective line 22 
off hook, apply a dial tone, and give a "busy" signal to any other line 
which attempted to call the customer at that moment. Therefore, because 
signal shifting means 34 capacitively couples to the customer's line and 
does not affect the line's status, both incoming and outgoing calls can 
proceed normally and will not be affected by the presence of signal 
shifting means 34. 
Modem 54 or other re-transmitting means is designed for operation within 
the passband of the telephone system, i.e., in-band frequencies, such as a 
Silicon Systems SSI173K222L-IP and related components. Modem 54 is 
connected through relay 102 to a separate, independent link from switch 38 
which is assigned to signal shifting means 34. Signal shifting means 34 
answers calls directed to it over its link. Scanning means 50 further 
includes a demodulator 112 such as Exar's XR-2211P integrated circuit and 
related components such as band pass filter 114, so constructed as to 
detect signals in the selected out-of-band frequency range, in one 
embodiment selected as 20 kHz and 22 kHz. Demodulator 112 is designed to 
detect and discriminate between these two frequencies, which represent a 
binary one and zero, respectively. The output port 62 of demodulator 112 
is connected to microcontroller 108 and thereby to modem 54. Various 
additional components provide protection against noise, lightning and 
other surges. 
Because signal shifting means 34 must function on long or very high 
impedance lines, the embodiment shown in FIG. 5 includes an "aspirating" 
feature in its power supply. Comparator 106 signals microcontroller 108 
when the line voltage on line 36 falls below a predetermined value, 
causing microcontroller 108 to shed all deferable current loads and to 
enter a low-power "sleep" mode so as to allow the line voltage to recover 
and to replenish the charge on the power supply's large input capacitor. 
When comparator 106 signals that line 36 has sufficiently recovered 
microcontroller 108 resumes normal operation. The practical effect of this 
arrangement is that the unit adjusts itself to the line impedance, 
producing only occasional brief pauses between characters on a line whose 
impedance would otherwise prevent operation entirely. 
To read a meter using an embodiment of the present invention, a computer 72 
or other command means at the utility office utilizes a modem 70 or other 
communication means to dial the ordinary telephone number of the 
respective signal shifting means 34 to which the meter 24 to be read is 
connected. Whereas initially signal shifting means 34 is without power and 
inactive, its ring-detect circuit 100 is activated by the ringing signal 
and trips relay 102, connecting modem 54 and its large (2200 mF) capacitor 
across tip and ring lines of the incoming (calling) line 36. As this 
capacitor begins to charge, the telephone switch 38 interprets the inrush 
current to mean that the line has been answered and removes the ringing 
signal from the line. After a few seconds (a function of line impedance) 
comparator 106 senses that the capacitor has reached a predetermined 
voltage and turns on the DC-to-DC converter which supplies 5 VDC to the 
remaining circuits in signal shifting means 34. Once the 5 VDC is stable, 
microcontroller 108 initializes itself, modem 54, and the selectively 
controllable switches 116, issues a prompt to the utility computer 72 and 
monitors modem 54 for a password and subsequent commands defining what 
data to collect and send. If an incorrect password is received, or if 
nothing is received from the utility computer 72 for about thirty seconds, 
signal shifting means 34 terminates the call. Upon receiving a proper 
password and a valid reading command, however, signal shifting means 34 
activates the proper switch 116 and capacitively couples to the customer's 
line 22 to which the meter of interest is connected. Demodulator 112 
informs microcontroller 108 whether it detects a signal in the range 20-22 
kHz: if so, microcontroller 108 reconstructs the encoder's message from 
the stream of ones and zeroes detected by demodulator 112, checks for 
proper parity and format, and causes modem 54 to return this message to 
utility computer 72 in the form of a sequence of conventional modem tones. 
(If the demodulator fails to find the expected 20-22 kHz "carrier" the 
controller issues an error message and awaits further instructions.) In 
this manner all meters connected to the customer lines within a particular 
telephone company interface box can be read via a single telephone call to 
signal shifting means 34, and one or more signal shifting means can be 
called simultaneously, many of which will serve several hundred lines each 
from large telephone company interface boxes. There is thus effected a 
means of reading meters rapidly without employing the telephone test 
trunk, without adding significant traffic through the telephone switch, 
without interference with or by the customer's use of the telephone line, 
and without the delay of other systems which cannot function while the 
line is in use. 
The present invention is also directed to a method for customer information 
communication between a customer, either residential or commercial, and a 
requesting location 40 over existing communication lines 22. Such methods 
may be practiced using the apparatus described above and illustrated in 
FIGS. 1 to 5. Communication lines suitable for use with the present 
invention would include any installed link such as traditional tip-ring 
wire pair type telephone lines or cable television lines. The information 
exchange is initiated by a request for customer information, such as a 
utility meter reading, which is transmitted from a requesting location 40, 
such as a utility company office, by telephone. Other types of information 
could include alarm readings, demand recorder readings, voltage data, or 
other status or meter type information. 
The invention could also be used where a customer control message is 
transmitted rather than an information request, thereby requiring only one 
way communications between the remote requesting location and the 
customer. For example, the control message could be sent to a switch in a 
customer's residence to trigger turning on the customer's lights or 
heater. Such a customer control request could also be transmitted from a 
requesting source such as a utility company to control electrical service 
or telephone service connection to the customer. Communications could also 
be one way from the customer to the requesting location 40 wherein 
information transfer would occur without requiring an initiating request 
from the requesting location 40. 
The telephone link 36 from the utility company 40 is routed through a 
telephone company switch 38 like any other phone call. This telephone link 
36, like existing voice communications, may occur over a tip-ring wire 
pair, a pair-gain or subscriber line carrier system, or using known 
cellular telephone methods. On a pair-gain system, demultiplexers on the 
subscriber side of the central office switch may employ frequencies in the 
8-10 kHz range which may be present on the existing communications line 22 
over which the present invention maintains substantially transparent 
communications. The call from the utility company, rather than being 
directed to a specific customer's residence, is picked up by a signal 
shifting means 34 at an intermediate local distribution point located 
between the telephone company switch station and the customer's residence. 
A telephone company interface box is one acceptable local distribution 
point. 
The request for customer information is received at the local distribution 
point by the signal shifting means 34. The request for customer 
information is then transferred from the local distribution point to the 
customer over existing communication lines 22 modulated at a first 
out-of-band frequency range as an out-of-band frequency request. The 
out-of-band frequency range is determined based on the frequency 
characteristics of communications line 22 and of the existing receiver 21, 
for example the customer's telephone. The frequency for the out-of-band 
frequency range is chosen to allow information to be exchanged over the 
existing communication lines 22 without disrupting existing uses, such as 
customer voice communications over existing telephone lines. For an 
embodiment of the present invention using existing telephone lines, the 
out of band frequency could be between about 20 kHz and 100 kHz. 
The out-of-band frequency request from the local distribution point is 
received at the customer's residence to provide an information request to 
the customer. The request may be received by an acquisition means 20 which 
is in turn electrically connected to the device information is requested 
from, for example, one of the customer's utility meters 24. The 
appropriate customer information is electrically encoded responsive to the 
information request to the customer. For example, if the information 
requested is a gas meter reading, an encoding means 30, such as the Cain 
Encoder.TM., converts the utility dial reading into an electrically 
encoded signal representing the customer's present gas meter reading. 
Alternatively, the request could initiate direct reading from a counter 
which is photoelectrically incremented by each turn of the meter's 
rotating disc. Either approach provides a meter reading. 
Once the electrically encoded customer information is generated it is 
transmitted over the existing communications lines 22 modulated at a 
second out-of-band frequency range as an out-of-band frequency information 
reading. The use of two different out-of-band frequency ranges allows 
requests from the local distribution point and information from the 
customer's residence to be transmitted over the existing communication 
lines simultaneously as shown generally in FIG. 2. The out-of-band 
frequency information reading is then received at the local distribution 
point. Finally, the out-of-band frequency information reading from the 
local distribution point is re-transmitted at in-band-frequencies through 
a telephone company switch 38 back to the requesting location. 
The present invention is also directed to a method for automated utility 
meter reading over a telephone line 22 of a residential or commercial 
customer operating independently of whether a request is initiated from a 
remote location. One or more of the customer's utility meter readings is 
electrically encoded as discussed above. The electrically encoded readings 
are then transmitted onto the customer's telephone line 22 as an 
out-of-band frequency reading signal by modulating the utility meter 
readings. This reading may be operatively transmitted over the customer's 
telephone line 22 regardless of whether the customer's phone 21 is on or 
off hook and may be transmitted concurrently over the customer's telephone 
line 22 between the customer and the local distribution point even if 
customer voice communications are underway. 
The encoding and transmitting steps may be performed one or more times. 
This encoding and transmitting may occur on a continuous basis or at 
predetermined intervals or responsive to an out-of-band frequency request 
transmitted from the local distribution point over the customer's 
telephone line 22 between the customer and the local distribution point. 
The request initiating encoding and transmitting may originate at the 
local distribution point or at a remote location 40 or from a customer's 
location as with alarm signals. 
Selected out-of-band frequency readings are received at a local 
distribution point. The selection could be based on the type of utility 
meter reading desired, for example gas or electric. Alternatively, the 
selection could be based on time interval, for example, where the encoding 
and transmitting is performed continuously, the readings could be read at 
the local distribution point only at fixed intervals or responsive to 
requests transmitted to the local distribution point from a remote 
requesting location 40 such as a utility company. 
The received selected out-of-band frequency readings are converted to data 
readings at the local distribution point. The out-of-band frequency 
readings reflecting the utility meter readings may be demodulated to 
provide data readings. The data readings are then selectively 
re-transmitted as in-band frequency reading signals over a telephone link 
36 connecting through a telephone company central office switch 38. The 
selective re-transmission could be determined based on the type of meter 
reading to assure that the appropriate information was transmitted only to 
the proper requesting location: for example, to insure that only gas meter 
readings were sent to the gas company. The in-band frequency reading 
signals are acquired at one or more remote locations 40 through the 
telephone company central office switch 38 to provide the customer's 
utility meter readings automatically to the remote locations. 
The step of selectively re-transmitting the readings may be initiated by 
transmitting a request from a remote location 40 over the link 36 
connecting through the telephone company central office switch 38. 
Furthermore, where the selective re-transmitting is based on meter type, 
this selection may be made responsive to the request from the remote 
location. 
The methods of the present invention may be used for automated reading of 
one or more types of utility meters of a plurality of customers. For 
example, each customer's residence could have both gas and electrical 
meters accessible from a plurality of remote locations including the gas 
company and the electrical company. Furthermore, a plurality of customer's 
residences could be accessible from each local distribution point. For 
example, when using existing telephone lines as the communications line 22 
and a telephone company interface box as the local distribution point, an 
entire neighborhood might be accessible from a single local distribution 
point which would contain a juncture point for the telephone line 
connection between all of those customers and the telephone company 
central office station 38. 
Where multiple customers each having one or more meters linked into the 
system are serviced from a given local distribution point, the method of 
the present invention may include additional selection operations after 
the acquisition of customer information and prior to re-transmitting 
selected information to the remote location 40 wishing to receive the 
information. The step of converting the received out-of-band frequency 
readings to data readings may be performed for selected customers 
accessible from that local distribution point. The selected customers may 
be only a single customer or all customers accessible from that local 
distribution point. Information may be obtained from one or more of the 
meters 24 or other devices 26 at the customer's location from which 
information is available. The data readings may then be grouped prior to 
re-transmitting the information to the remote location or locations. 
In one embodiment, the grouping step involves selecting the reading from a 
first type of utility meter from all of the customers to provide a data 
reading packet including the last reading from the first type of utility 
meter from all customers having the first type of utility meter. For 
example, the most recent gas meter readings from all of the accessible 
customers could be grouped into a data reading packet which is then 
selectively re-transmitted to the gas company. 
The determination of what to include in the data reading packet may be made 
responsive to a request from the remote location. Where the encoding and 
transmitting of the customer information is performed continuously, the 
steps of receiving, converting and grouping the information may be 
performed each time the encoding and transmitting step is repeated to 
provide a data reading packet representing the last reading received from 
the customer. The step of re-transmitting may then be performed each time 
an updated data reading packet is created to continuously provide to the 
remote location 40 the last utility meter reading or other information 
from each of the selected customers. Alternatively, the step of 
re-transmitting could be performed responsive to a request from the remote 
location 40. 
The foregoing description is illustrative of the present invention, and is 
not to be construed as limiting thereof. The invention is defined by the 
following claims, with equivalents of the claims to be included therein.