Note: Descriptions are shown in the official language in which they were submitted.
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METHOD AND APPARATUS FOR TRACING REMOTE ENDS OF
NETWORKING CABLES
Field of the Invention
This invention relates to a method and apparatus for readily tracing remote
connective portions of networking cables. It also provides a means for
visually
identifying the cabling from a. computer workstation to a workstation panel
and to a
hub that connects the computer workstation to a server. This invention also
includes a circuit that allows a light emitting diode (LED) to be~connected
across
two pairs of interconnecting wire cable without disrupting those pairs for
carrying
data between the server and the workstation.
Background of the Invention
The purpose of any networking cable is to carry data from one computer-
related device to another. Computer-related devices include terminals,
personal
computers, printers, workstations, hubs, switches, storage devices, tape
drives, and
servers. Networking cables, frequently referred to as "jumper cables",
"jumpers",
or simply "cables", typically are multiple pair copper wires packaged in an
outer
flexible sheath. Networking cables are designed to interconnect a computer-
related
device with another computer-related device. Such networking cables often are
used in systems where there are many networking cables connected to frames or
panels, each of which may have many connecting cables and which may be located
closely adjacent other similar panels, sometimes without carefully regimented
management of the cables. The connections of each cable may be remote from one
another, even being in separate rooms or spaces, whereby the networking cables
may be of substantial length.
One example of such use of networking cables is in computer centers where
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it is often necessary to connect a networking cable from an individual
workstation
at one location with another networking cable from a computer server remote
from
the workstation. Further the interconnections sometimes are located in crowded
and/or cramped quarters. Tracing and identifying a remote connector section or
end
of a specific cable for changing its connection in a network or to facilitate
replacement often is difficult, tedious and time consuming, and can lead to
errors
which create further service problems and additional costs.
Various methods and systems have been developed for locating the ends of
a networking cable. One such method is a trial and error process that requires
personnel to use test equipment at both ends of each and every wire pair to
identify
the termination points. This process may be labor intensive and expensive. The
second method is a variation of the first method and involves the use of
equipment
to send a tone on a wire pair and then detect a particular frequency at the
termination point. This process is also labor intensive. Also, to determine
termination points, the cable needs to be disconnected from the computers
connected to the network. As a result, these methods interfere with
performance
and require the workstation to be taken out of service. In addition, both
systems
require the test person to walk from one end of a test point to the other end.
If the
workstation and server are located in separate rooms or in remote locations,
the
previous methods are labor intensive and inefficient for easy detection of
termination ends.
In the telecommunications context, Patent 5,666,453 discloses a specialized
fiber optic jumper cable for tracing remote connective portions of a fiber
optic
cable which includes a composite fiber cable, fiber optic connectors,
electrically
G
powered light emitting devices at the connectors, and a pair of electrical
conductors
embedded in the cable, with one or more electrical power connectors for
selectively
applying an external electrical power source to the light emitting devices. An
LED
and an electric power connector suitable for plug-in connection of a power
pack are
affixed to the cable adjacent each end such that both LEDs are lighted
whenever
power is applied to either of the electrical connectors. The attendant
illumination of
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the LEDs provides an indication that the tracer system is activated and
functioning
properly and readily indicates where both ends of the same jumper cable are
located. The electrical conductors also may be used for convenient telephonic
communication by service personnel.
There is a need fox an improved mode of readily tracing networking cables
to easily and accurately identify a remote portion, and particularly to
identify a
remote end.
Summary
The present invention provides a method and apparatus for readily tracing
networking cables. A networking cable having features of the present invention
comprises a plurality of copper wire pairs encased in a flexible sheath for
effectuating transmissive interconnections, electrically activated telltales
affixed to
both ends of the cable for providing an identification signal when activated,
and
means for selectively applying a current to the cable that activates the
telltales. A
power pack may be provided for applying a current through the electrical power
controls so that upon application of the current the telltales are activated
and the
networking cable is visually identified. In a preferred embodiment of the
present
invention, the power pack provides for telephonic communication through the
networking cable. Another embodiment of the present invention includes a
networking cable as described above except with one end having a connector
mateable with an eight conductor modular connector such that a standard
networking cable may be converted into a networking cable usable for tracing
cable
ends.
Brief Description of the Drawings
FIG. 1 is an illustration of a typical computer network employing the
teachings of this invention.
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FIG. 2 is a schematic illustration of a networking cable employing teachings
of this invention.
FIG. 2A is a schematic illustration of a networking cable as in FIG. 2.
FIG. 3 is an enlarged view of the connector, telltale, and electric power
connector of FIG. 2.
FIG. 4 is an enlarged view of the networking cable of Fig. 2 illustrating one
end of the networking cable mating with a plug.
FIG. 5 is an illustration of a portable battery power source for activating
the
telltales of the networking cable of FIG. 2, and illustrating the inclusion of
a
telephonic device for communication over the networking cable.
FIG. 6 is a schematic illustration of the indicator circuit used in the
networking cable of FIG. 2.
FIG. 7 illustrates an embodiment of the present invention wherein the
networking cable 34 of FIG. 2 is replaced with a networking cable of five
unshielded twisted copper pairs.
FIG. 8 illustrates an embodiment wherein a networking cable adapter
embodies the teachings of the present invention.
FIG. 9 illustrates an electrical power circuit of the power pack 50 in FIG 5.
While the invention will be further described in connection with certain
preferred embodiments, it is not intended to limit the invention to those
embodiments. On the contrary, it is intended to cover all alternatives,
modifications and equivalents as may be included within the spirit and scope
of the
invention.
Detailed Description of a Preferred Embodiment
FIG. 1 illustrates a typical multiple computer environment which includes a
plurality of computer workstations 9, 96, 97 and 103, computer laptops 94, 99
and
101, and peripheral devices 91, 98, and 104 linked by networking cable to data
hubs 3 and 112 and computer servers 1 and 113. Typically, a computer room 108
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houses the computer servers 1 and 113 and data hubs 3 and 112 of the computer
network. Located separately, such as in room A 90, room B 95, room C 102, room
D 100, and room E 93, are the computer workstations and the various devices of
network. Devices include computer equipment, printers, scanners, and
terminals.
Between the computer workstations 9, 96, 97, and 103 and the servers 1 and 113
is
a workstation panel 8 that holds the networking cable. The workstation panel
may
be located in the computer room 108 or may be located in a separate location
such
as what is known as a "closet." From the workstation panel 8 networking cable
is
used to connect the computers 9, 96, 97 and 103 to a hub 3, and 112 of one the
servers l, and 113. A typical computer network may use Ethernet as the
protocol to
support data transfer between computer and server pairs. Data includes
distinct
pieces of information. Each computer workstation or computer laptop is
associated
with one particular computer server. For example, in FIG. I, John's
Workstation 9
may be supported by computer server 1 and John's Workstation 9 may
communicate with computer server 1 by utilizing the Ethernet protocol.
FIGS. 2-3 illustrate a networking cable which may be used in the computer
environment of FIG. 1. The networking cable includes a composite cable 34 with
a
connector 33 at each end and an electrically operated telltale device 31
adjacent
each of the connectors 33. The illustrated cable 34 includes four insulated
twisted
copper wires 36 encased in an outer cover jacket layer 37. In a preferred
embodiment, the composite cable includes four copper wire pairs as is
specified by
Category 5 cabling standard, a Bellcore standard defined by an industry
consortium. There may be more wire pairs for enhancement and/or protection of
data transmission rates. In an embodiment of the invention as is illustrated
in FIG.
7, five wire pairs are encased in the composite cable. In such ~an embodiment
where five wire pairs are encased in the composite cable the networking cable
is
referred to as a "cablefmder" networking cable. Also, the composite cable may
consist of coaxial, twinaxial, twisted, untwisted, shielded and unshielded
pair wires,
as is known in the art. Accordingly, the term "networking cable" is used in
this
description and in the appended claims to encompass all such variations of
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composite cable. Further, the various coating and covering components and
variations thereof to form a basic networking cable are known in the
networking
cable art and will not be further described herein.
The illustrated telltale 31 is a light emitting diode (LED) mounted in a
support block 35. A power connector also is provided immediately adjacent the
LED and includes a pair of male contacts 32 for receiving appropriate plug
prongs
of a power source such as the battery pack unit 50 shown in FIG. 5.
Each of the electrical wires 36 is a small metallic electrical conductor, e.g.
twisted copper pair, covered by a suitable insulation sheath. The wires 36 are
embedded in the cable 34, preferably throughout its length at the time of
manufacture of the cable. The electrical wires 36,are connected to the power
connector 32 and to the telltales 31 such that upon applying electrical power
through electrical wires 36, the telltales 31 are activated. Exposed end
portions of
the electrical wires 21,27 are physically and electrically connected to the
leads
20,2 of the power connector 32 in any appropriate manner, for instance by
being
crimped in end portions of the power connector in a known manner or by other
solderless termination techniques or by soldering. A flexible electrically
insulated
boot 35 surrounds the exposed ends of the wires 36 and the electrical
interconnection with the telltales 31 and the power connector 32 to retain
these
components in assembled relation on the cable as well as to provide electrical
insulation protection for the interconnections.
Referring now to FIG. 3, the connectors are located on the ends of the
length of the cable 34 and may be of any suitable design, such as six or eight
conductor modular connectors. A type of six conductor modular connector that
is
used in Category 3, a Bellcore standard (as mentioned previously) defined by
an
industry consortium is the so-called RJ-11 connector. The illustrated
connectors 33
are of the RJ45 type (an eight conductor modular connector), each comprising
eight
leads which are fixed in a housing. A latch 54 that is part of the housing
includes
an elongated locking mechanism for engaging a pin of a mating device 42 to
effect
a coupling affixation to such mating device 42. FIG. 5 illustrates such a
situation.
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The right end of the connector 33, as seen in FIG. 5, illustrates a typical
connector
end for mating with a connector 42 and having a locking mechanism S4 for
engaging in a slot 55 for retention purposes.
Referring to FIG. 6, in a preferred embodiment of the invention, a
networking cable indicator circuit is connected to two 21,27 of the four
electrical
wires 36. The DC inputs to the networking cable indicator circuit are
connected
across the third twisted wire pair 20,21 and the fourth twisted wire pair
27,28 of the
networking cable. Although in a preferred embodiment, the third and fourth
pairs
are chosen, any two pairs may be used so that when power is not applied across
the
wires, data transmission is not affected. Further, in an illustrated
embodiment as in
FIG. 7, the networking cable indicator circuit may be connected to a fifth
pair 41 so
that when power is applied across the wires, data transmission is not
affected. Such
a preferred embodiment is called a "cable finder" networking cable.
The DC inputs to the networking cable indicator circuit are connected
across two pairs (20, 21 and 27, 28) through a diode 22, light emitting diode
(LED)
23, CMOS switching field effect transistor (FET) 25, zener diode 24, and
resistor
26 which together implement the indicator circuit. A device suitable for use
as a
CMOS switching FET is available as model 2N7000 from Motorola Corp. of Santa
Clare, CA. A device suitable for use as a diode is available as model IN4148
from
Motorola of Phoenix, AZ. Any suitable low current diode with a reverse
breakdown higher than any expected voltage is suitable for the indicator
circuit.
Further, a preferred embodiment includes a 12-volt LED, a 7.3-Volt zener diode
and a 16 M Ohm resister.
The indicator circuit is described as a high impedence LED-FET circuit.
The indicator circuit is in a high impedance state if normal data transmission
takes
place. Normal data transmissions are defined by the Category 5 standard to
take
place at less than 7-Volts. For the Category 5 standard, when the voltage
across the
transmission wires 36 is less than 7 volts, then the indicator circuit appears
to be
invisible to data transmission and the impedance across the circuit is high.
Whenever the voltage across the indicator circuit is greater than 7 volts,
current
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flows through the circuit and the impedance across the circuit is low. A
voltage
greater than 7 will cause the FET to break down and the current to flow to
light the
LED.
The indicator circuit of FIG. 6 is designed so that when a higher voltage
then the normal voltage (7-Volts for Category 5) on the wires 36 is placed
across
the wires (20, 21 and 27, 28), then the circuit is in a low impedance state.
If the
voltage across the pair exceeds 7-Volts, then the impedance goes to the
impedance
of the LED, which is relatively low. In terms of current, the current flow
across the
LED at 12 volts is about 10 mA which is sufficient to illuminate the LED.
Conversely, in the high impedance state, the current flow across the LED at
less
than the normal voltage of 7-Volts, is less than 10 uA. Although the circuit
was
designed for the normal voltage of 7-Volts, any pre-selected level may be
chosen.
Thus, an indicator circuit that is designed for a normal voltage of less than
7-Volts
is considered to be equivalent. An equivalent circuit is any circuit that goes
across
those wires which does not allow significant current flow until you have
applied an
outside stimulus such as a 12-Volt power supply.
In a preferred embodiment, a FET is used to perform the switching function
of turning on when the voltage is greater than the preselected level of 7-
Volts. A
switching relay, a programmable gate array or a programmable digital computer
may perform this function. Such various switching elements and variations
thereof
are known in the computer art and will not be further described herein.
In a preferred embodiment, a 12-Volt LED and 12-Volt technology is used.
This allows 12 volts to be available for the telephone. Further, the various
LED,
resistor, and current limiting diode combinations are known in the art and
will not
be further described herein. In an embodiment of the invention where the
handset
for the telephone talk circuit is not necessary, less than I2-Volt technology
may be
used in place of the 12-Volt technology. Further, using a higher voltage
technology, such as 15-Volt LEDS or 24-Volt LEDS is also possible.
In another embodiment of the present invention, in place of the indicator
circuit of FIG. 6, an LED 31 and power connector pins 32 are directly
connected to
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the fifth pair 41 of transmission wires as illustrated in FIG. 8. This fifth
pair 41
provides the tracing feature of the networking cable without interfering with
data
transmissions.
Referring to FIG. 5, a battery pack 50 includes a drycell battery, e.g. 12
volts, in a housing. The battery is suitably connected to a pair of external
leads in a
short, e.g. 8" flexible cable 53 which carries a power plug connector 45 that
is
mateable with the contacts 31. The pack 50 also supplies 12-Volt DC power to
the
jack 43 of telephonic device 47. Referring to FIG. 9 for example, the battery
pack
circuitry includes a 12-Volt DC battery 69, a 600 ohm'/4 watt resistor 77, a
RJ11
jack 43 and a connecting cord 53 with .025 pin connector 45. In another
arrangement, in place of the battery 69, a 15-Volt DC power supply may be
provided which operates from a standard electrical outlet (typically on a
wall) and
connects to the battery pack. In yet another arrangement, a power supply may
be
provided which operates from a conventional 120-Volt AC power circuit which
generates a DC power output.. Accordingly, the term power pack is used in this
description and in the appended claims to encompass all such variations of
power
packages.
Whether powered by an internal battery or using external power, the power
pack preferably is portable for movement from work station to work station,
and
may be hand held or temporarily mounted adjacent a frame or panel such as by a
clip or Velcro~ securement. However, the power pack also may be a fixed
installation, such as for panels and racks which serve a large number of
networking
cables. The leads 32 may be fixed to the power pack or may be patchcords,
particularly in installations which include a fixed power pack, and may be
free
cords or may be mounted on automatic take-up reels or other forms of automatic
returns.
Upon applying electrical power to the wires 36, as by the simple act of
plugging in the battery power pack 50 to a power connector 32, the LED
telltales
31 will be lighted. For example, a user who has identified one connector end
of a
computer network networking cable to be traced may plug the power pack into
the
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conveniently adjacent power connector 32. The attendant illumination of the
adjacent LED will signal that the telltale tracer system is operating. The
user then
seeks a correspondingly illuminated and hence readily visible telltale at
another
location to readily locate and identify the other terminal end. Further, in a
multiple
computer network interconnected by networking cables of the present invention,
plugging the power pack into the power connector near a computer workstation
will
correspondingly illuminate the corresponding LEDs at a patchpanel 8, attached
networking cables and associated computer server 1. Further, in a multiple
computer network interconnected by networking cables of the present invention,
electrical power may be applied by pressing a soft-key or function key on a
keyboard of the workstation 9 will correspondingly illuminate the
corresponding
LEDs at a patchpanel 8, attached networking cables and associated computer
server
1. The workstation may be wired so that pressing a soft key will provide
electrical
power to the networking cable. For example, a computer technician in a remote
computer room 108 may call John at his workstation and ask him to press <F12>
on the keyboard so that the corresponding LED at the server in the computer
room
108 will be lit.
It will be appreciated that various telltale devices may be utilized,
including
for example conventional small light bulbs or liquid crystal or electro-
mechanical
indicators suitably mounted in the desired positions along the cable 34,
wherever
ease of identification is desired. For example, a light bulb or liquid crystal
visual
indicator may be substituted for each LED in a system as described with
reference
to FIGS. 2-8. One example of an electro-mechanical device such as may be used
is
a "Faranti Indicator", which has a movable disk that exposes either a flat
black
surface or a bright contrasting surface to the viewer as the device is
subjected to
successive electro-magnetic pulses. The use of LEDs presently is preferred for
simplicity and ruggedness. Further, different color telltale devices may be
utilized
for ease of identification. For example, a red colored LED may be used to
signify
an important computer connection that may not be disturbed.
Providing telltales and power connections separate from the connectors
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permits use of the system in networking cables using any type of cable
connectorization. Also, the relative positions and orientation of the telltale
and the
power connector may be varied.
Referring now to FIG. 8, in an embodiment of the present invention an
adapter is provided so that existing networking cables may be modified to
provide
the tracing feature. Such an adapter may be termed a "portfinder" adapter.
Adapter
79 consists of the RJ45 mateable connector 42, composite cable 34 with
attendant
electrically activated telltales 31, RJ45 connector 33 as illustrated in FIG.
1 and
indicator circuit as illustrated in FIG. 6. The RJ45 mateable connector 42
connects
to so called standard "patchcables" or "jumpers". A computer network that is
fully
connected using standard "patchcables" or "jumpers" may be converted to the
networking cable of this invention by using the adapter 79. Further, the
adapter 79
provides for the tracing feature to a computer workstation, such as
workstation 9 in
FIG. 1. When adapter 79 is attached to an existing standard patchcable and
power
is applied to power pins 32, attached networking cables of this invention will
illuminate. The cablefinder adapter allows for tracing of remote ends of
cables
from a computer workstation to a computer server.
The use of a portable plug-in battery pack provides a simple, flexible and
cost-effective approach to powering and selectively activating the telltales.
For
example, the pack 50 of FIG. 5 may be clipped to a service person's belt for
convenient use at any location. However, in some installations power may be
supplied from fixed outlets associated with the cross connect system hardware
which uses the networking cables, with voltage and current control,provisions
suitable to the electrical conductors and telltale devices being utilized.
Electrical
switches then may be provided at convenient locations, in lieu of the power
connectors 32, for activating one or more of the telltales along a cable. An
"alert"
signal means, such as a sound emitting device, may be added at some or all
indicator positions for activation by the same internal electrical signal
power
system simultaneously with activation of the visual indicators. This will
serve to
alert a worker to look for an activated visual telltale.
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As indicated in FIGS. 5 and 9, the internal electrical conductors 36 also may
serve for telephonic communication, such as between service personnel at
positions
remote from one another, in the manner of so-called "order wires" heretofore
provided in wiring cables in telephone communications systems. Appropriate
telephone jack sockets 43 may be provided at the respective positions, such as
in
association with the power connectors 32 or preferably in the power pack 50,
to
receive the jacks of telephonic device 47.
Further, a method of finding computer workstation and computer server/hub
pairs is disclosed. However, it will be appreciated that this method may be
used to
find any device at the end of a networking cable. For example, a printer
connected
via networking cable may be located by use of this method.
The invention has been described in considerable detail with reference to
certain embodiments, and particularly with respect to the currently preferred
embodiments thereof. However, it will be understood that variations,
modifications
and improvements may be made, particularly by those skilled in this art and in
light
of the teachings referred to herein within the spirit and scope of the
invention as
claimed.
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