US2282900A - Telephone system - Google Patents

Telephone system Download PDF

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Publication number
US2282900A
US2282900A US329404A US32940440A US2282900A US 2282900 A US2282900 A US 2282900A US 329404 A US329404 A US 329404A US 32940440 A US32940440 A US 32940440A US 2282900 A US2282900 A US 2282900A
Authority
US
United States
Prior art keywords
relay
line
test
circuit
over
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US329404A
Other languages
English (en)
Inventor
Stehlik Rudolph Frank
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Associated Telephone and Telegraph Co
Original Assignee
Associated Telephone and Telegraph Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Associated Telephone and Telegraph Co filed Critical Associated Telephone and Telegraph Co
Application granted granted Critical
Publication of US2282900A publication Critical patent/US2282900A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/22—Arrangements for supervision, monitoring or testing
    • H04M3/26—Arrangements for supervision, monitoring or testing with means for applying test signals or for measuring
    • H04M3/28—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor
    • H04M3/30—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop

Definitions

  • the present invention concerns improvements in or relating to telephone systems and more particularly concerns improved arrangements for testing of subscribers lines.
  • This lock-out arrangement puts the subscribers line into an unsatisfactory condition for testing purposes and the object of the present invention is to provide means whereby all connections to the subscribers line which is being tested may be removed while testing is taking place.
  • a cut-off relay is alone operated over a line which has a low resistance shunt persistent thereon and the cut-off relay and the line relay are energised in series to establish a through connection for said line to common exchange apparatus which has been previously selected
  • a further feature of the invention consists of providing means for applying a high potential to the line relay to cause it to energise when the cut-off relay is alone energised so as to establish a through connection independently of the selection of common exchange apparatus whereby the line may be tested independently of either the connection of the cut-off relay or other connections from common exchange apparatus.
  • Figure 1 illustrates a known line circuit of a subscriber.
  • Figure 2 illustrates a circuit at a test desk
  • Figure 5 illustrates a test distributor modified for the. purpose of the invention but otherwise known
  • Figure 6 illustrates a known final test selector.
  • Relay L in operating an armature Ll prepares a circuit for relay K, at the same time as it controls at armature L2 a common starting circuit over armature K4 for an idle or preselected line finder.
  • the line finder finds the calling line a circuit is completed over the test conductor P for relay K over armature LI and resting contacts of armature Kl.
  • Relay K operates and while it opens at armature K2 the circuit through the right-hand winding of relay L it opens at armatureKl a short circuit across the left-hand winding so that relays L and K are both operated in series and remain operated in series throughout the connection.
  • relay L being quick acting releases and relay K being slow to release remains operated until a locking circuit is completed for it over the subscribers loop including armatures L3, L4 and K2.
  • relay PG common to a number of lines operates over armatures K3 and L5 and an alarm is given.
  • test circuits of Figure 3, and its continuation Figure 3a, Figure 4 and its continuation Figure 4a. are known and it is only necessary for the purpose of describing the invention to refer to them in general terms.
  • the circuit of Figure 3 is provided with keys for bringing into play as required, a graduated howler G. H., a loud speaker L. S. and a dial switch tester D. T. together with access over leads V0 to an operator, while the circuit of Figure 4 is provided with keys for bringing into circuit a dial switch over leads VD for setting up connectionsto the different subscribers lines to be tested, means for talking to a subscriber over leads VR, a voltmeter V, and transmission testing means TTM.
  • test operator wants to test a line in the condition described above, that is to say a line of which the relay K is alone energised over the subscribers loop, then he inserts one of the plugs PGI' or PGZ into the jack J of the test distributor circuit Figure 2.
  • leads MI, M2, STI, STZ to the left of Figure 2 are connected to the correspondingly designated leads of the test distributor of Figure 5 and while the first pair of leads Ml, M2 are utilised for setting up the connection the second pair STI, STZ are used for test purposes being freed from feeding bridges and the like.
  • the operation of the dial switch if the reversing key RK is suitably operated as well as the appropriate key to connect up the dial switch, will cause impulses to be transmitted over leads MI and M2 to first cause thetest distributor TD to set itself with its wipers upon contacts leading to the final test selector FTS of Figure 6.
  • the wipers V, R and Z of test distributor TD come into direct connection with the vertical magnet VM, the rotary magnet RM and the release magnet ZM of the final test selector FTS which is thereby directly under the control of relays associated with the test distributor and for that reason is provided with no individual controlling relays.
  • the final test selector is therefore set after the test distributor and a through connection now exists from the cord circuit of Figure 4 or Figure 3 if the reversing key RK is switched over via the springs of the jack J, armatures TTI and TTZ of relay TT, leads STI and STZ ( Figures 2 and 5), armatures GI and G2. of relay G, wipers W2, WI of test distributor TD, leads FTZ, FTI of final test selector FTS, wipers FWZ, FWI to contacts T2, Tl of Figure 1 to the line which it is desired to test. If the line had not been in the condition described it would have been possible to proceed to test the line in the usual way but as it is the connection of the relay K across the line will militate against making a clear test. In these conditions relays G and H are operated in known manner. The operator presses the key KPG ( Figure 2) which on operating completes a circuit over the positive lead STI to the relay FL via armatures G3, Hl.
  • Relay FL on operating at armature FLA closes a circuit around its lower winding so as to render it slow to release, at armature FLB completes the circuit for slow relay FLI, and at armature FLC opens a short circuit across the secondary of the transformer TF in the test lead to wiper WP leading through the final test selector, Figure 6, to the private wire terminal TP of Figure 1, at the same time placing earth between the relay RC and the secondary winding referred to.
  • Relay FLI at armature FLIA in conjunction with relay FL completes a circuit for the primary winding of transformer TF, the effect of which in conjunction with armature FLD of relay FL is to send a monetary high voltage pulse over wiper WP through the left-hand winding of relay L until relay FL releases.
  • Relay L in these conditions operates and in doing so opens the circuit of relay K across the loop at armatures L3 and L4.
  • Relay K however remains operated as Well as relay L via earth connected up at armature FLC by relay FL in the test distributor, Figure 5.
  • relay FL releases followed by relay FLI.
  • Relay RC operates in this circuit and establishes a locking circuit for itself over armature RCI independently of the latter part of the circuit described. Relay RC at armature RC2 also opens the locking circuit of relay G and connects earth via armature PC!
  • Relay G on releasing at armature G3 opens the connection of both relays FL and FL! to the test leads so that now direct connections to the subscribers line can be traced without any earth or battery connections thereto, thereby rendering it possible to test the subscribers line.
  • the test distributor and test final selector are released and the removal of earth from the private conductor TI? releases relay L so that relay K again becomes locked over the subscribers line if the short circuit still persists.
  • test operators position test switches controlled from the position to seize such lines, means on said line controlled from said position over said switches for causing said electrical connections to be removed from a seized line, and means controlled from said position for testing said line independently of said connections while said shunt remains thereon.
  • a telephone system such as claimed in claim 1 wherein said last means consists of a relay associated with the line, and means controlled over the test switches for momentarily operating said relay, and means controlled by said relay for removing the said electrical connections and then disconnecting itself from the line.
  • a line, a line and cut-01f relay therefor means for causing the operation of the cut-off relay only when a fault occurs on the line, test equipment for seizing said line while the cut-off relay is operated under such a condition, means controlled over the test equipment for energizing the line and cut-off relays in series to place the line in normal condition for test irrespective of the low resistance shunt existing thereon.
  • a telephone system such as claimed in claim 1 having means in the test position for causing a momentary connection ofhigh potential to the seized line over the test switches, and said means on the line is responsive to such high potential to remove the electrical connections.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Monitoring And Testing Of Exchanges (AREA)
US329404A 1939-05-22 1940-04-13 Telephone system Expired - Lifetime US2282900A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB15248/39A GB529644A (en) 1939-05-22 1939-05-22 Improvements in or relating to telephone systems

Publications (1)

Publication Number Publication Date
US2282900A true US2282900A (en) 1942-05-12

Family

ID=10055691

Family Applications (1)

Application Number Title Priority Date Filing Date
US329404A Expired - Lifetime US2282900A (en) 1939-05-22 1940-04-13 Telephone system

Country Status (3)

Country Link
US (1) US2282900A (enrdf_load_html_response)
BE (1) BE440078A (enrdf_load_html_response)
GB (1) GB529644A (enrdf_load_html_response)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3657714A (en) * 1970-06-10 1972-04-18 Electro Devices Inc Ground eliminator system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3657714A (en) * 1970-06-10 1972-04-18 Electro Devices Inc Ground eliminator system

Also Published As

Publication number Publication date
BE440078A (enrdf_load_html_response)
GB529644A (en) 1940-11-26

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