Title: Ring, tip, ground testing tool
Abstract: An apparatus and a method for determining faults in a telephone line. The apparatus has an enclosure housing a switch. The switch is for electrically communicating with a ring wire of a telephone line, with a tip wire of the telephone line, and with an electrical ground. The switch selectively permits electrical communication between any two of the ring wire, the tip wire, and the ground. The apparatus improves testing of the telephone line by helping identify an electrically open condition in the telephone line.
Patent Number: 6,940,949 Issued on 09/06/2005 to Forsberg
| Inventors:
|
Forsberg; Kevin (Orlando, FL)
|
| Assignee:
|
Bellsouth Intellectual Property Corporation (Wilmington, DE)
|
| Appl. No.:
|
282564 |
| Filed:
|
October 29, 2002 |
| Current U.S. Class: |
379/21; 324/509; 379/22.03; 379/27.01 |
| Intern'l Class: |
H04M 001/24; H04M 003/08; H04M 003/22 |
| Field of Search: |
379/101,21,220.3,220.7,24,270.1,270.6,290.2,220.6,290.5,320.1
324/509,510,522,525,539
|
References Cited [Referenced By]
U.S. Patent Documents
| 3704347 | Nov., 1972 | Brown.
| |
| 3792205 | Feb., 1974 | O'Dea.
| |
| 3975600 | Aug., 1976 | Marston.
| |
| 4022987 | May., 1977 | O'Dea.
| |
| 4159402 | Jun., 1979 | De Graauw et al.
| |
| 4186283 | Jan., 1980 | Simmonds.
| |
| RE31728 | Nov., 1984 | Simmonds.
| |
| 5123041 | Jun., 1992 | Brinkmoeller.
| |
| 5218616 | Jun., 1993 | Stephens.
| |
| 5754624 | May., 1998 | Sullivan et al.
| |
| 5933011 | Aug., 1999 | Atkins.
| |
| 5960060 | Sep., 1999 | Kaibel.
| |
| 6438212 | Aug., 2002 | Lysaght et al.
| |
| 6614880 | Sep., 2003 | Lysaght et al.
| |
Primary Examiner: Tieu; Binh K.
Attorney, Agent or Firm: Walters & Zimmerman, Medlin; Jennifer, Mitchem; Todd
Claims
1. An apparatus, comprising:
an enclosure housing a switch, the switch having three poles, a first pole connected
to a ring wire of a telephone line, a second pole connected to a tip wire of the
telephone line, and a third pole connected to a ground;
the switch having three positions that selectively permit electrical communication
between any two of the ring wire, the tip wire, and the ground,
wherein the apparatus improves testing of the telephone line by helping identify
an electrically open condition in the telephone line.
2. An apparatus according to claim 1, further comprising a first terminal in
electrical communication with the switch, the first terminal for electrically communicating
with the ring wire of the telephone line.
3. An apparatus according to claim 1, further comprising a second terminal in
electrical communication with the switch, the second terminal for electrically
communicating with the tip wire of the telephone line.
4. An apparatus according to claim 1, further comprising a third terminal in
electrical communication with the switch, the third terminal for electrically communicating
with the ground.
5. An apparatus according to claim 1, wherein the switch has a first position
for directly connecting the ring wire to the ground.
6. An apparatus according to claim 1, wherein the switch has a second position
directly connecting the tip wire to the ground.
7. An apparatus according to claim 1, wherein the switch has a third position
directly connecting the ring wire to the tip wire.
8. A method, comprising:
establishing electrical communication between a testing cool and a ring wire
of a telephone line, a tip wire of the telephone line, and a ground, the testing
tool comprising an enclosure housing a switch, the switch having a first pole connected
to the ring wire, a second pole connected to the tip wire, and a third pole connected
to the ground;
selecting one of three positions of the switch to establish electrical communication
between any two of the ring wire, the tip wire, and the ground, such that the switch
has a first position that electrically connects the first pole and the second pole,
a second position that electrically connects the first pole and the third pole,
and a third position that electrically connects the second pole and the third pole;
and
measuring a resistance in at least one of the ring wire, the tap wire, and the
ground,
wherein the measured resistance indicates whether a fault is present in the telephone
line.
9. An apparatus, comprising:
an enclosure housing a switch, the switch having a first pole, a second pole,
and a third pole, the first pole directly connecting to a ring wire of a telephone
line, the second pole directly connecting to a tip wire of the telephone line,
and the third pole directly connecting to an electrical ground;
the switch having a first position that electrically connects the first pole
to the second pole;
the switch having a second position that electrically connects the first pole
to the third pole; and
the switch having a third position that electrically connects the second pole
to the third pole,
wherein the apparatus improves testing of the telephone line by helping identify
an electrically open condition in the telephone line.
Description
NOTICE OF COPYRIGHT PROTECTION
A portion of the disclosure of this patent document and its figures contain material
subject to copyright protection. The copyright owner has no objection to the facsimile
reproduction by anyone of the patent document or the patent disclosure, but the
copyright owner otherwise reserves all copyrights whatsoever.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention generally relates to telephony and, more particularly, to testing
of telephone lines for electrical faults.
2. Description of the Related Art
Telephone customers sometimes experience static on their telephone line.
Static in a may be caused by corrosion, condensation, or even a break in the telephone
line. Static may also be caused by a loose connection between the telephone line
and a telephone. Whatever the causes of static, nearly sixty percent (60%) of customer
complaints in some areas are due to static in the telephone lines.
Resolving customer complaints of static can be frustrating for telephone
technicians. Ambient temperatures, for example, can mask a problem with a customer's
telephone line. Sometimes the copper core of a telephone line is only partially
cut, creating a "high resistance open" condition. That is, there is a connection
at the cut, but the connection is dependent upon the ambient temperature. As the
telephone line heats up during the day, the copper core expands and maintains a
good connection. When night falls, the copper core cools, shrinks, and causes static
on the telephone line. When the technician tests the telephone line during the
day, the expanded copper core passes a good dial tone and the technician finds
no trouble. The customer, however, still experiences static at night, so another
technician is dispatched to repair the same complaint.
This complaint process continues until one or more later technicians suspect
a high resistance open condition. Because the telephone line heats and expands
during the day, an experienced technician will spray the telephone line with water
from a hose. The water eventually cools the telephone line, causing the copper
core to shrink. When the technician now tests the telephone line, the partially
cut copper core is revealed as a high resistance on the telephone line, indicating
an open condition. Although the technician has finally discovered the problem,
two hours or more have been spent before the technician even begins a repair.
There is, accordingly, a need in the art for improved testing of telephone
lines, a need for determining the causes of static in a telephone line, a need
for quickly determining whether a high resistance open condition exists on a telephone
line, and a need for improved testing of telephone lines that reduces labor times.
BRIEF SUMMARY OF THE INVENTION
These and other problems are reduced by an apparatus and a method that helps
determine problems with a telephone line. This invention quickly and simply attaches
to the telephone line and allows a person to quickly determine whether an open
condition exists with the telephone line. One embodiment of this invention describes
an apparatus for determining faults in a telephone line. The apparatus has an enclosure
housing a switch. The switch is for electrically communicating with a ring wire
of a telephone line, with a tip wire of the telephone line, and with an electrical
ground. The switch selectively permits electrical communication between any two
of the ring wire, the tip wire, and the ground. The apparatus improves testing
of the telephone line by helping identify an electrically open condition in the
telephone line. The terms "electrical communication," "electrically communicates,"
and "electrically communicating" all mean the transmission of current and voltage
between the switch and the ring wire, the tip wire, and the electrical ground.
Electrical communication is commonly achieved when the switch makes electrical
contact with the ring wire, the tip wire, and the electrical ground, thus allowing
current and voltage to flow. Electrical communication, however, is also possible
by electromagnetic induction.
Another embodiment of this invention describes a method for determining faults
in the telephone line. Electrical communication is established between a testing
tool and a ring wire of a telephone line, a tip wire of the telephone line, and
an electrical ground. The testing tool comprises an enclosure housing a switch.
A position of the switch is selected to establish electrical communication between
any two of the ring wire, the tip wire, and the ground. When electrical communication
is established, a resistance is measured in at least one of the ring wire, the
tip wire, and the ground. The measured resistance helps determine whether a fault
is present in the telephone line.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
These and other features, aspects, and advantages of this invention are better
understood when the following Detailed Description of the Invention is read with
reference to the accompanying drawings, wherein:
FIGS. 1 and 2 are isometric drawings of a testing tool 10 according
to an embodiment of this invention;
FIG. 3 is a series of schematics illustrating the operation of the switch 16
shown in FIGS. 1 and 2; and
FIG. 4 is a flowchart illustrating a method for determining faults in a telephone
line according to an embodiment of this invention.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1 and 2 are isometric drawings of a testing tool
10 according
to this invention. FIG. 1 shows the testing tool
10, while FIG. 2 shows
the testing too
10 connected to a telephone line
12. As FIG. 1 shows,
the testing tool
10 comprises an enclosure
14 housing a switch
16.
The switch
16 electrically communicates with at least one of at least three
terminals. A first terminal
18 is shown as a wire conductor
20 and
an adjustable clip
22. The wire conductor
20 communicates current
and voltage from the adjustable clip
22 to the switch
16. A second
terminal
24 and a third terminal
26, likewise, also include respective
wire conductors
28,
30 and adjustable clips
32,
34
to communicate current and voltage to the switch
16.
FIG. 2 shows the testing tool
10 connected to the telephone line
12.
Because the testing tool
10 may be used throughout a telecommunications
network, FIG. 2 simply conveys a generic connection to the telephone line
12.
The telephone line
12 has an outer jacket
36 shielding a ring wire
38 and a tip wire
40. The ring wire
38 runs from the central
office (not shown) of the telecommunications network (not shown). The ring wire
38 typically connects to a telephone (not shown) and transmits signals from
the central office to the telephone. The tip wire
40 completes the electrical
loop by returning signals from the telephone to the central office. The ring wire
38 and the tip wire
40 are the typical copper telephone lines running
throughout many homes and businesses.
FIG. 2 shows the testing tool
10 connected to the telephone line
12.
The ring wire
38, for example, is clamped to a ring wire screw terminal
42. The adjustable clip
22 of the first terminal
18 is also
clamped to the ring wire screw terminal
42. The first terminal
18
then electrically communicates with the ring wire
38 of the telephone line
12. Any current and voltage in the ring wire
38 is electrically communicated
from the adjustable clip
22, through the wire conductor
20, and to
the switch
16. The tip wire
40 is clamped to a tip wire screw terminal
44, and the adjustable clip
32 of the second terminal
24 is
also clamped to the tip wire screw terminal
44. The second terminal
24
electrically communicates with the tip wire
40. Any current and voltage
in the tip wire
40 is electrically communicated from the adjustable clip
32, through the wire conductor
28, and to the switch
16.
FIG. 2 also shows the testing tool
10 connected to electrical ground.
The third terminal
26 is grounded. The third terminal
26 electrically
communicates with the electrical ground when the adjustable clip
34 is clamped
to a grounded screw terminal
46.
The switch
16 has at least three (3) positions. A first position permits
electrical communication between the ring wire
38 and the electrical ground
(such as the grounded screw terminal
46). A second position permits electrical
communication between the tip wire
40 and the electrical ground. A third
position permits electrical communication between the ring wire
38 and the
tip wire
40. Although the switch
16 is shown as a rotary switch,
the switch
16 may be any design that permits electrical communication between
any two of the ring wire
38, the tip wire
40, and the electrical
ground. Rotary switches, rocker switches, toggle switches, and slide switches are
but a small listing of the various switch designs that are applicable to this invention.
Use of the testing tool
10 will now be explained. The testing tool
10
is connected to the telephone line
12 and used to detect a high resistance
open condition. Although the testing tool
10 may be used throughout the
telecommunications network, this explanation will assume the testing tool
10
is connected to an Outside Network Interface (not shown). The Outside Network Interface
is the point of connection between the customer's premises and a Public Switched
Telephone Network. The Outside Network Interface often demarcates the physical
and electrical boundary between the customer's premises and the telecommunications
network. Most people know the Outside Network Interface as the "phone box" on the
side of a house. The telephone line
12 typically runs from a telephone pole,
to the house, and into the Outside Network Interface (or phone box). Although the
testing tool
10 could be connected to other network elements in the telecommunications
network, a connection to the Outside Network Interface is most commonly envisioned
by the inventor.
FIG. 2 also represents a connection to the Outside Network Interface. The Outside
Network Interface has the ring wire screw terminal
42, the tip wire screw
terminal
44, and the grounded screw terminal
46. The ring wire
38
is clamped to the ring wire screw terminal
42 and the tip wire
40
is clamped to the tip wire screw terminal
44. The adjustable clip
22
of the first terminal
18 is clamped to the ring wire screw terminal
42,
and the adjustable clip
32 of the second terminal
24 is clamped to
the tip wire screw terminal
44. The adjustable clip
34 of the third
terminal
26 is clamped to the grounded screw terminal
46. The testing
tool
10 is thus connected to the ring wire
38 and the tip wire
40
of the telephone line
12, and the testing tool
10 is thus connected
to electrical ground.
The testing tool
10 cleverly allows a person to test the telephone line
12 for a high resistance open condition. When, for example, the core of
the telephone line
12 is only partially cut, the telephone line
12
will frequently test perfect. If, however, either the ring wire
38 or the
tip wire
40 is shorted to electrical ground, a resistance measurement on
either line will indicate the presence of the open condition. When the ring wire
38, for example, is shorted to electrical ground, creating a "hard short"
on the ring wire
38, an only slightly shorted resistance measurement indicates
a problem. The term "hard short" means two wires, such as the ring wire
38
and the grounded third terminal
26, are directly connected. Direct continuity
is what's desired when one line, such as the ring wire
38 or the tip wire
40, is shorted to electrical ground. Because a hard short should read zero
ohms (0 Ω), a resistance measurement of twenty or thirty ohms (20 Ω
or 30 Ω), indicates something is wrong. The resistance measurement should
be zero, one, or two ohms (0 Ω, 1 Ω, or 2 Ω), reflecting the
hard short. This procedure, of applying a hard short and measuring the resistance
on the line, applies to either the ring wire
38 or the tip wire
40.
A person tests either the ring wire
38 or the tip wire
40 (e.g.,
just one side of the telephone line
12) and tries to isolate which side
(or both ring wire
38 and the tip wire
40) has the high resistance open.
Now that the basic principles of this invention have been explained, a more detailed
use of the testing tool
10 is now described. The testing tool
10,
as described above, is connected to the telephone line
12. The switch
16
is set to either of its three (3) positions, permitting electrical communication
between any two of the ring wire, the tip wire, and the ground. The switch
16
thus electrically shorts any two of the ring wire, the tip wire, and the ground.
While the switch
16 may be set to either position, this explanation will
start with the switch
16 set to the third position for permitting electrical
communication between the ring wire
38 and the tip wire
40.
The third position of the switch
16 electrically shorts the ring wire
38 to the tip wire
40. Once the switch
16 is set to the third
position, the person performing the test then travels to the other opposite end
of the telephone line
12 and measures the resistance on the ring wire
38
and the tip wire
40. If, for example, the telephone line
12 runs
from a telephone pole to a house, the person travels to the telephone pole and
takes resistance measurements. Because the switch
16 is set to the third
position, thus electrically shorting the ring wire
38 to the tip wire
40,
the resistance measurement should read zero to perhaps seven ohms (0 Ω-7
Ω). If the high resistance open condition is located very close to the testing
tool
10 creating the electrical short, the resistance measurement should
be about zero ohms (0 Ω). If the high resistance open condition is located
about 1,200 to about 1,500 feet from the testing tool
10, the resistance
measurement should be about zero to about three ohms (0 Ω-3 Ω). If
the high resistance open condition is located about 5,000 feet from the testing
tool
10, the resistance measurement should be about seven to about ten ohms
(7 Ω-10 Ω). When, however, the hard short is applied, and the resistance
measurement is about thirty to about forty ohms (30 Ω-40 Ω), something
is wrong. The resistance measurement should indicate the presence of the hard short,
but a moderate short is, instead, measured. This moderate short indicates a high
resistance open is somewhere in the telephone line
12.
Now that the moderate short is detected, the testing tool
10 is used to
further isolate the high resistance open condition. The testing tool
10
is then set to the first position. The first position permits electrical communication
between the ring wire
38 and the electrical ground, thus shorting the ring
wire
38. The person performing the test travels to the other opposite end
of the telephone line
12 and measures the resistance on the ring wire
38.
The resistance measurement, as before, should read zero to perhaps seven ohms (0
Ω-7 Ω), reflecting the hard short. If, however, the resistance measurement
is about thirty to about forty ohms (30 Ω-40 Ω), this moderate short
indicates a high resistance open is somewhere in the ring wire
38.
The testing tool
10 is also used to test the tip wire
40. The testing
tool
10 is set to the second position. The second position permits electrical
communication between the tip wire
40 and the electrical ground, thus shorting
the tip wire
40. The person performing the test travels to the other opposite
end of the telephone line
12 and measures the resistance on the tip wire
40. The resistance measurement, as before, should read zero to perhaps seven
ohms (0 Ω-Ω), reflecting the hard short. If, however, the resistance
measurement is about thirty to about forty ohms (30 Ω-40 Ω), this moderate
short indicates a high resistance open is somewhere in the tip wire
40.
The testing tool
10 also helps determine when the trouble lies in another
portion of the telephone line
12. When the testing tool
10 applies
the hard short, and the resistance measurement indicates zero ohms (0 Ω),
this portion of the telephone line
12 is good. That is, in this example,
no high resistance open condition occurs in the telephone line
12 running
from the telephone pole to the house. The testing tool
10 would be removed
from the Outside Network Interface and installed in another portion of the loop.
Other portions of the loop would be tested to find the high resistance open, short,
or grounded condition.
FIG. 3 is a series of schematics illustrating the operation of the switch
16.
FIG. 3A illustrates the first position of the switch
16. This first position
creates a shorted, direct connection between the ring wire
38 and electrical
ground, thus permitting electrical communication between the ring wire
38
and the electrical ground. FIG. 3B illustrates the second position of the switch
16. This second position, likewise, creates a shorted condition between
the tip wire
40 and electrical ground, thus permitting electrical communication
between the ring wire
40 and the electrical ground. FIG. 3C illustrates
the third position of the switch
16 that permits electrical communication
between the ring wire
38 and the tip wire
40, thus shorting the ring
wire
38 to the tip wire
40.
FIG. 4 is a flowchart illustrating a method for determining faults in a telephone
line. An electrical communication is established between a testing tool and a ring
wire, a tip wire, and grounded electrical (Block
48). A position of a switch
is selected (Block
50) to establish electrical communication between any
two of the ring wire, the tip wire, and the electrical ground. A resistance is
measured (Block
52) in at least one of the ring wire, the tip wire, and
the electrical ground. The measured resistance identifies whether a fault is present
in the telephone line.
While the present invention has been described with respect to various features,
aspects, and embodiments, those skilled and unskilled in the art will recognize
the invention is not so limited. Other variations, modifications, and alternative
embodiments may be made without departing from the spirit and scope of the present invention.
*
