US2201651A - Dial switching telephone system - Google Patents

Dial switching telephone system Download PDF

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Publication number
US2201651A
US2201651A US200656A US20065638A US2201651A US 2201651 A US2201651 A US 2201651A US 200656 A US200656 A US 200656A US 20065638 A US20065638 A US 20065638A US 2201651 A US2201651 A US 2201651A
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earth
circuit
relay
wire
group
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US200656A
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English (en)
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Hatton William
Haigh Leslie Baines
Kozma Ladislas
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AT&T Corp
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Western Electric Co Inc
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M15/00—Arrangements for metering, time-control or time indication ; Metering, charging or billing arrangements for voice wireline or wireless communications, e.g. VoIP
    • H04M15/04—Recording calls, or communications in printed, perforated or other permanent form
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M15/00—Arrangements for metering, time-control or time indication ; Metering, charging or billing arrangements for voice wireline or wireless communications, e.g. VoIP
    • H04M15/08—Metering calls to called party, i.e. B-party charged for the communication
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/08—Indicating faults in circuits or apparatus
    • H04M3/12—Marking faulty circuits "busy"; Enabling equipment to disengage itself from faulty circuits ; Using redundant circuits; Response of a circuit, apparatus or system to an error

Definitions

  • This invention relates to electrical communication systems and more particularly, though not exclusively, to automatic ticketing equipment for use in such systems.
  • Oneobiect of the invention is to provide improved substation identifying equipment which allows identification of any substation of an exchange in an economical and expeditious manner.
  • one feature of the invention comprises a telecommunication exchange system comprising subscriber identifying equipment, characterized in this, that two stages of subscriber identifying switches or the like look for marking conditions applied to a circuit connection terminating at one end ina subscriber's line to be identified.
  • Another object of the invention is to provide improved means for ensuring that operating procedure in interstation connections is not prejudiced bythe use of faulty equipment.
  • a second feature of the invention comprises an electrical communication system comprising a number of-similar 25 equipments, any idle one of which can be used in a connection, characterized by automatic test circuits in said equipments which test certain devices therein for faults immediately the equipments are taken into use, and by circuits closed if a fault exists in an equipment to disconnect and busy the equipment, to cause another equipment to be connected up in its place, and to give an alarm.
  • the same calling line identification equipment can be used for identifying calling subscribers of a plurality of different hundred-line groups.
  • the identification may be made in a plurality of stages.
  • the calling partys number and the record of the duration of the connection can both be made without delaying the normal release of a connection.
  • a minimum holding time for a completed connection is enforced unless before that time expires certain records incidental to charging for the connections have been made.
  • common-equipment used temporarily e. g.. for automatic ticketing purposes
  • a similar equipment which is also tested before use.
  • a common voice-frequency signal-receiving valve circuit may be so tested.
  • Fig. 1 shows part of a subscriber's line circuit
  • first line finder a first line finder, a second line finder, and a first group selector together with a complete identification line finder.
  • the latter is one of a group of identical circuits and is adapted to have access to the subscribers lines served by a plurality of groups of first line finders;
  • Fig. 2 shows an identification control circuit which is one of a group of identical circuits and is adapted to have access through its finder CF to a plurality of identification finders belonging to one or more groups of such finders and through its finder IF to a plurality of groups of first line finders;
  • Fig. 3 shows a two-wire junction circuit outgoing to another automatic exchange and adapted to be associated with a printing register whereby a tangible printed record may be produced for each call established over the junction;
  • Fig. 4 shows a control circuit common to a plurality of outgoing junction circuits and adapted to be connected to the outgoing junction for a portion at least of the duration of its occupation by a call;
  • Fig. 5 shows an identification startingcircuit and distributor
  • Figs. 6 and '7 which should be placed one above the other show alternative identification equipment.
  • the ticket printing machine to which the bracketed conductors of Fig. 3 extend may be of the type disclosed in British Patent 472,435 granted to L. Devaux.
  • a first line finder such as ILF is caused to rotate until its brushes a b c d rest upon the terminals of the calling line
  • a second line finder such as finder ZLF is caused to rotate until itsbrushes a, b, c, it rest upon the terminals individual to the aforesaid first line finder
  • a register circuit (not shown) is caused to associate itself with the aforesaid second line finder in a well-known manner.
  • the calling subscriber then dials the number of the wanted subscriber and the register causes the first group selector IGS permanently associated with the second line iinder 2L1, to select an outgoing junction, Fig. 3, in response to one or more digits of the number dialed, e. g., the first two digits of a five digit number.
  • the register is adapted to await the closure of a low resistance loop across brushes a, b, of the first group selector IGS before transmitting each of the remaining digits, e. g.. the last three digits of the number dialed.
  • Relay Jc When the outgoing junction circuit, Fig. 3, is seized, relay Cw energizes to earth on the 0 wire and energizes Jo. Contacts 105 remove earth from wire 6 extending to the ticketing machine.
  • Relay Jc now operates via deZ, 112, sil, m. followed by Ri; Ri, idl, id, 1216, ml, to earth on wire 5 from the ticketing machine associated with the junction circuit.
  • Relay Jd energizes via cs6, resistance RST, jsm'i, eel, riZ, xii, 102, and operates JSM via 0.04, mi, M3, dai.
  • Relay Jb energizes via 10!, jet, a loop circuit via the Junction and the incoming Junction circuit, iel and coil JA. Bb also operates via 116, esl, jbl, 192.
  • Js is now looped across the incoming a and b wires and operates followed by JI, and Je; Je, bbl, :iel, 7'32. Je locks via b123, jei, 1112. Jo also locks via jel, ⁇ 02, 1.92.
  • the locking circuit for Jo is also opened by 582 and J0 releases opening'the loop circuit for .lb which releases.
  • An impulse is sent over the outgoing junction by the opening of the circuit of Jb, but on the release of Js at the end of the incoming impulse, battery is connected via 79, job, jsl, to the junction b wire, and earth via id to the junction 0 wire, to end the outgoing impulse.
  • Js repeats the remaining impulses of the first digit to the printer magnet and over the junction.
  • Relay Si remains energized until the end of the digit, when ED is released at sii disconnecting 58 from the junction. to release J8 and to signal the register-controller. Jl is also released, together with Je.
  • Contacts bbl maintain battery on the 12 wire when contacts :Isl open to prevent an extra impulse being sent.
  • Jd reoperates in the same circuit as before followed by J SM.
  • Earth connected to wire 2 by the ticketing machine is now connected via 7222, 1%, to wire 3 to cause the digit to be printed and the digit wheel to be returned to normal.
  • Ri has been locked via ni, gig! to wire 5 of the machine from which earth potential is now removedduring the revolution of the operating shaft MCS of the machine (not shown) so that Ri releases, followed by Jd and JSM, and JS steps to its third position.
  • Js is now connected to the incoming a and 12 wires to signal the register to send the tens digit.
  • J1 and Je are operated and- Jc locked.
  • the tens digit is transmitted andrepeated by Js to the machine and over the junction and switch JSM is stepped to position 4, after which the same switching operations take place as after the hundreds digit, JBM being stepped to position I. when the machine has printed the digit and signaled to the junction circuit, the latter in turn connects Js to the junction to signal the register.
  • the units digit is transmitted and repeated in the manner before described.
  • Switch JS steps to position 8 during receipt of the units digit.
  • Si releases as before followed by Bb, Je, J8, and the circuit for J! is opened.
  • Jd re-energizes together with JSM, and at the same time N! is operated; N rid, esl, Tml, jam! in position t, est, ril, xii, 102. N! operates because resistance RST is no longer in its circuit as it was in positions l-I of JS.
  • nil connect earth continuously to wire 3 to the machine to inform it that no more wanted party digits are to be awaited.
  • the machine prints the units digit, and removes earth from wire 5 to release R! which releases Jd, and JS steps to position 1.
  • N! locks via nil and wire 4.
  • Es operates via act, nil, jal.
  • the ticketing machine When the ticketing machine arrives in position 8, after printing the units digit, it removes earth from wire 4 to release Nf, which removes earth from wire 3. The machine'then self-steps to position l0 and again connects earth to wires 4 and I.
  • Jc is again energized via ae2, ri2, ail. 7'92.
  • J b When the called party replies, J b energizes over the distant loop and earth via 10!, jbl, cal,
  • Ts releases, opening the circuit of JSM which steps switch JS to position I in which Wp operates via 71!, tml, a'sm2, eel, M2.
  • JSM is stepped in this manner after each six seconds of conversation starting from position 1.
  • a facility governed by a manual key such as CRK may be brought into use to party's number positions.
  • Magnets CJM of all free ticketing control circuits' are operated and the, switches CJ hunt for the outgoing junction circuit, Fig. 3.
  • Vp energizes and releases Te and Dt.
  • the circuit of CJM is opened at UM, Vp looks at vpi, lamp L0 is flashed and an audible alarm may also be given.
  • Vp may also be operated over its other winding I if the battery supply fails or if the circuit is held for an unduly long time, in which case battery via cam CM first operates Th and later VP.
  • Vt is energized via tc6, dtl, and contacts vt4 connect 500 cycle current to grid transformer AGT.
  • the valve RV becomes conducting and An operates followed by Tc, which lights lamp LO steadily via vp3, tcl.
  • Vt is released and 500 cycle current' removed from AGT so that Ap releases.
  • the ticketing machine is ready for tariff it energizes Ri over wire 5, followed by slow-release relay Pw via Z02, cgimi, n'Z, Fig. 3, sil, dgZ.
  • Relay also operates via edi, p203, tji, dti, followed by Ed; earth, ccmZ, Bd, ed i, 1'02, battery.
  • the circuit for Ed is only effective when interrupter INR removes earth from In.
  • Bd When INR removes earth, Bd energizes and connects INR to 11' which is operated when INR connects earth thereto.
  • bcli energizes CCM until INR releases Ir when switch CC takes a first step.
  • Ir also connects earth from tfli via ir3, cjm3, wire i, Fig. 3, to the ticketing machine.
  • INR continues to impulse Ir which steps CC and. the printer magnet of the machine insynchronism for the first tariff digit.
  • T1 When the machine is again ready after the ,fourthtarifl digit-is printed, Ri, Fig. 3, and Pw, Fig. 4, energize and this time T1 immediatelyoperates via tit, p102, cdmt, nti, mi, and opens the circuit of lo.
  • Relay Ir energizes via tj3, pw2, cdml, nti, pii.
  • Relay T locks in parallel with lamp LA via til, tci, cdmi.
  • Earth via tfl, th3, ir5, is connected to start lead SVL for the distributor circuit Fig.5 for the calling party identification control circuits.
  • 2000 cycle identification current is connected via 1'14, tf5, cjm5, to the conversational fourth wire d, Fig. 3, over which the current flows back to the first line finder circuit and the calling partys line circuit.
  • Relay Ab is normally operated so long as DS has access to an idle identification circuit. If a call comes in while Ab is released, AI is energized to operate an alarm and a congestion meter.
  • Distributor switch DS is normally standing on an idle identification control circuit, Fig. 2. Earth via st5, dsml is connected to the filament of valve DV, Fig. 2, and winding of relay Vp in parallel, and 500 cycle current via sti, dsm2 is connected to the identification circuit.
  • valve DV If the valve DV is faulty, Vp energizes, locks via vpi, operates an alarm via 21122 and lead ALL, flashes lamp LO via V123, earths lead FTL to operate As, Fig. 5, via dsm3, and busies the identification circuit to group relay Ab, Fig. 5 by opening V125. If As operates and Ab is energized,
  • next identification circuit If this is busy, earth via gfi back and scm3 or sdm3 off normal, or earth via gti front is connected to FIL to step DS, Fig. 5'on another step.
  • Relay A operates in the anode-cathode circuit of DV. Earth via a'i, gt2, gjl, energizes Str. Earth is now connected from jtG via shit and lead RTL to operate D, Fig. 5.
  • D operates DR which disconnects the 2000 cycle current from the transformer RGT. Relays Rp, So, St, therefor release and 500 cycle current is disconnected from lead VFL, Fig. 2.
  • Relay D also operates magnet DSM.
  • Magnet CFM is now energized via gt3, gf3, strl, ai, and switch CF looks for the link circuit forming part of the conversational connection.
  • switch CF looks for the link circuit forming part of the conversational connection.
  • 2000 cycle current via lead i2, Fig. 2,.jd, Fig. 5, wiper cfmB, Fig. 2, gti, GT renders the valve DV conducting and A again operates.
  • G! is now energized via gt2, al and locks via all, str2.
  • Gt is now released followed by A.
  • Ft energizes via ftl. It ⁇ . 018, strl. al and locks via ft, stri. Earth via ltl, cfm'l energizes Fd, Fig. 5, to disconnect the 2000 cycle current from the banks of the switches CF.
  • Relay Ft also releases D, Fig. 5, which in turn releases DSM and distributor DS steps on to another identification circuit.
  • Magnet IFM now energizes via ti, U6, fti and switch IF hunts for an idle identification line finder RI, Fig. 1, which has access to the lines connected to the link circuit to which CF is connected, under control of relay-T.
  • T energizes via #5, wiper cfml, z'JmO, cross-connection, ifma, lead 8, battery, Fig. 1.
  • T disconnects IFM so that switch- IF stops.
  • Lt operates via tl, U5, iii and connects busy earth via low resistance, left-hand winding of T and lt4 to busy the selected finder RI.
  • Earth via ml is now connected via 10, (U2, U2, to battery, so that Is energizes when short-circuiting earth via interrupter INT is removed. 10 then locks via ic3, energizes If, and connects INT to relay I.
  • I On its first energization, I operates SCM, and 500 cycle current is connected via TR, i3, ifml, cfmfi, lead 9, H], or ii, one of wipers rima-rimc, wipers di, d2, d3, of the line finders and group selector back to the automatic ticketing equipment.
  • Switch SC homes; SCM, interrupter, ici, and icZ, scml.
  • Relay Th. now energizes via cdm3, ntl, ml, and locks via. th3, til.
  • Relay IT is released when brush cdm3 leaves position 5 and lamp LA ceases to glow.
  • the 2000 cycle signal over the conversational fourth wire is disconnected at in, and the start signal is disconnected at thi from lead SVL so that relay SV, Fig. 5, releases.
  • the first and second digits in the example given are exchange code digits and are therefore known.
  • the second terminal of sdml is crossconnected to the required wire l-8.
  • the thousands digit is then sent, the number of impulses being determined by a circuit via sdmi and its fourth contact, cjm2, and a contact of semi.
  • the value of the hundreds digit is determined by the connection via contact five of sdml, wiper cfml and the semi bank.
  • the tens and units digits are determined by the connection via the sixth and seventh contacts of sdml, z'fmS, and ifm5, leads 6 and 5, and wipers rimd and Time, Fig. l, in turn in the following manner.
  • Relay BI is shunted in this position by a 200 ohms resistance via scm2, fti, so that it is not able to operate if the ground on wire 4 is connected over a resistance. ground, however, the shunt mentioned has no effect. If D) does not operate SC advances on the next impulse to position 2, where Df remains connected over are scm2 to wire 4. The shunting resistance of 200 ohms is, however, disconnected and, therefore, if the wire I is grounded over a resistance of 1500 ohms (digit 2) D) will operate and stop sending. If this is not the case. SC continues to advance and the wires 2, 3 and 4 are consecutively tested in the manner described above.
  • wire 3 causes the machine to step to position 22 in which earth is removed from wire 4 to release Nf, removing the earth which had been connected via nfl to wire 3.
  • the release of A is followed by operation of Ar, via nsZ, ac6, wpl, 7'92.
  • Ar via nsZ, ac6, wpl, 7'92.
  • Jd is operated via mp2, arl, to ground on terminal 3 of CLC, connecting earth from es3, via M2, 1 13, to wire 3 in re-- sponse to which three minute-holes are punched by the machine in turn on the ticket, and the date, hour, and serial number are printed in turn, one with the punching of each minute hole.
  • Ri is released during these operations by removal of earth on wire 5, and W1), which no longer has a locking circuit via 10173 since Ac is released and Jd is operated, is released since its locking circuit via wp4, H2 is also opened.
  • the junction circuit is no longer held busy by the ticketing machine, Jd also releases.
  • JS has 22 positions, and its thirty-first step after position I on the first rotation determines the beginning of the fourth minute of conversation, that is, when it reaches position (7+31-22) IS on its second rotation. In this position, Wp
  • J S With Tm energized, JS steps to its first position immediately it reaches position 2
  • J S After passing position IS on the second rotation, J S only takes 20 steps per rotation at six second intervals, and the beginning of each additional minute occurs when JS reaches positions fi and 16 during each further rotation, the recording being caused by operation of Wp as before.
  • a relay Nt is provided and is operated from clock-controlled contacts via vtB to substitute wiper cdmZ for wiper cdm3 in the tariff-signaling circuits.
  • the identification start impulse over conductor SVL from the junction circuit used in a connection energizes relay Gs, Fig. 6, which in turn energize G1) in series (via r14) with relay Ci of an identification control circuit of the group controlled by a relay Gb. If all the circuits of this group were busy relay Ng would be operated to extend the start circuit to another group of identification control circuits.
  • Vd now operates via 1203 and oil and causes V0 and D0 to energize. The circuit of Vd is opened at v03 and it releases slowly, 2000 cycle current is connected during the time Vd is energized via vd2, doll, primary of transformer DT, dofl to earth.
  • Magnet IMM now operates via ot2, fh2, okl, arl and switch IM hunts for the group lines comprising the calling subscriber.
  • group lines comprising the calling subscriber.
  • a direct current test relay Mt is now connected to test for double connections; earth, of I, mtm2, muml, rZl, high resistance winding of Mt, btl, Zt3, immll to test battery. If no otheridentification control circuit has stopped on the same outlet Mt will operate and look over its low resistance winding in series Md which also energizes.
  • Relay Dc was energized when Bt operated via bt2, fhd.
  • magnet IFM When Md energizes, magnet IFM is operated via mdZ, fhl, jtl and IF hunts for an idle final selector in the group marked by the position of IM.
  • Ft When a selector is found Ft energizes: earth, 0102, imml3, ifml, Ft, mdl, z'fmii and wire 2 to idle battery potential on the final selector (FS) 0 wire.
  • the double test is performed by Ed and Pt and if IF is the only switch testing the final selector FS, Fd also operates followed by Fh to ot3 and Do to fhd. Contacts jh4 open the circuit of De which releases slowly.
  • Relay A1- which has been energized by the 2000 cycle current via IM is released by the operation of Do and Ai energizes via dol, af2, fh2, okl, arl.
  • A locks via dol, M2 and energizes Ta via 0J4, zt2.
  • the identification circuit has been held by the earth potentials supplied by contacts of 0t during the above operations.
  • earth via a 125-cycle filter is connected via USS, mtm3, 1mm wiper to the multiple point connection of the twenty marking wires including that of the calling line. This prevents low-frequency interference between the individual marking wires, while allowing an identification circuit to deal with another connection in the group.
  • Relay Rl is therefore energized via mum2, ltl.
  • RI locks via r12 and releases 0t and the other relays.
  • Relay X operates via interrupters of MTM, MUM, mtmZ, oil, and closes a circuit via :cl, mtml, for MTM.
  • Relay X interacts with MTM and MT homes.
  • Relay X then interacts with MUM and MU homes.
  • Earth is then connected via afl, mtmZ, muml, rll to short-circuit and release Rl.
  • relay Cw energizes via lt2, ifml, lead 3, and the 0 wire of F3, in parallel with the calling subscriber's cut-oil! relay, and earth via cwl, holds 01.. If release takes place during transmission of the calling party's number, Cw and 0t will release, and the identification circuit will return to normal.
  • the various digits are determined in the following way and are transmitted in well-known manner. In a six-digit area, the first two digits are known from the ofllce. These two invariable digits are sent in positions I and 2 of a sequence switch respectively.
  • the 1000s digit is determined by the position of IF, or in other words, by the group to which the engaged final selector belongs.
  • the 's figure is a function of the position of IF and that of the marker MU.
  • one group of final selectors gives access to 200 subscribers (odd-even hundreds). In the case of even hundreds, MU has received maximum 10 impulses only, during the units selection, whereas in case of an odd hundreds the final has sent 10 impulses more.
  • the 10's digit is indicated by the position oi MT.
  • the units digit is sent under the control of MU.
  • calling lines having marking terminals, two groups of identifying switches of which one group is 'used for terminating connections on said lines, means for imposing a test condition on the terminal of one of said calling lines, and means responsive to the presence of said test condition on said calling line for operating a switch in each of said groups of switches to connect with said terminal.
  • calling lines arranged in groups having both group and line marking terminals, a group of switches for line group identification, a group of switches for line identification, said last-mentioned group of switches being also used for extending talking connections to said lines when called, means responsive to a calling line initiating'a call for imposing a test condition in the group terminal and the line terminal of said calling line, means for operating one of said line switches for locating the terminal of said calling line, and means for operating one of said group switches for locating the group terminal of said calling line before said line switch locates said calling line terminal.
  • calling lines arranged in groups, each of said lines having a marking terminal, a group identifying switch and a line identifying switch accessible to said terminals, and a common test device associated with said group identifying switch for controlling the operation of said group identifying switch and of said line identifying switch when operated to locate the marking terminal ofa calling line, said line identifying switch also serving to complete talking connections to said lines when called.
  • calling lines having marking terminals, a called line, a group switch, switching selectors for establishing a connection between one of said calling lines and said called line, means for imposing a test condition on the terminal of said calling line, and. means responsive to the presence of said test condition on said calling line for operating said group switch to locate the group in which said calling line belongs and one of said selectors to locate the marked terminal in said group belonging to said calling line.
  • calling lines arranged in 'groupsand having marking terminals, called lines, a group identifying switch, final selectors for" completing connection between calling lines and called lines, means for imposing a test condition on the terminal of one of said calling lines, and means responsive to the presence of said test condition on the terminal of said calling line for operating said group switch to locate the group in which said calling line belongs and one of said final selectors to locate the marked terminal in said group which belongs to said calling line.
  • calling lines arranged in groups having both group and line marking terminals, a first group switch having access to said group marking terminals, a group of connector'switches having access to said line marking terminals, and a second group switch for engaging a free connector switch in said group of connector switches to connect withthe line marking terminal of a calling line.
  • calling lines having group marking terminals and line marking terminals, a group switch, final connectors for establishing connections to said lines when called, means for imposing a test condition on the group marking terminal of a calling line, means for imposing a different test'condition on the line marking terminal of said calling line, means responsive to the presence of said test condition on the group marking terminal of said calling line for operating said group switch to locate said group marking terminal, means respon sive to the engagement of said terminal by said group switch for seizing one of said final connectors to locate the line marking terminal ofsaid calling line, and means responsive to the test condition on said line marking terminal for stopping the operation of said final connector.
  • calling lines having group marking terminals and line marking terminals, a group switch, final connectors for establishing connections to said lines when called, means for imposing a test condition on the group marking terminal of a calling line, means for imposing a different test condition onthe line marking terminal of said calling line, means responsive to the presence of said test condition on the group marking terminal of said calling line for-operating said group switch to engage said group marking terminal, means responsive to the engagement of said terminal by said group switch for seizing one of said final connectors, and a counting circuit for selectively operating said final connector by revertive impulsesincluding means responsive to said test condition on the group marking terminal for causing said connector to select the group marked by said test condition and other means responsive to said different test condition on the line marking terminal for engaging the terminals of said line.
  • calling lines arranged in groups having a marking terminal for each group and a marking terminal for each line, a group switch,'groups of final connectors having access, respectively. to each of said groups of lines, means for imposing a test condition on the group marking terminal of a calling line.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Interface Circuits In Exchanges (AREA)
  • Monitoring And Testing Of Exchanges (AREA)
  • Meter Arrangements (AREA)
  • Selective Calling Equipment (AREA)
US200656A 1936-10-31 1938-04-07 Dial switching telephone system Expired - Lifetime US2201651A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB29638/36A GB484568A (en) 1936-10-31 1936-10-31 Improvements in or relating to telephone or like systems

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US2201651A true US2201651A (en) 1940-05-21

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US200656A Expired - Lifetime US2201651A (en) 1936-10-31 1938-04-07 Dial switching telephone system

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DE (2) DE887525C (xx)
FR (1) FR828570A (xx)
GB (3) GB484568A (xx)
NL (2) NL56019C (xx)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2597007A (en) * 1942-03-31 1952-05-20 Int Standard Electric Corp Common control circuit for operating switches rearward to calling line
US2621256A (en) * 1949-07-08 1952-12-09 Automatic Elect Lab Calling line identification apparatus
US2904635A (en) * 1950-03-02 1959-09-15 Siemens Ag Allocation of outgoing lines in automatic telecommunication systems
CN105545879A (zh) * 2015-12-04 2016-05-04 江西飞尚科技有限公司 一种基于单片机实现电磁换向阀控制器
CN105545881A (zh) * 2015-12-04 2016-05-04 江西飞尚科技有限公司 一种基于智能液压控制系统

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2908758A (en) * 1952-09-11 1959-10-13 Gen Telephone Lab Inc Toll ticketing telephone systems
DE1035703B (de) * 1957-04-26 1958-08-07 Siemens Ag Schaltungsanordnung fuer Fernmelde-, insbesondere Fernsprechanlagen mit Waehlerbetrieb, bei welchen Schaltglieder gemeinsam mehreren Verbindungswegen oder Verbindungseinrichtungen zugeordnet sind

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH134796A (de) * 1927-12-20 1929-08-15 Siemens Ag Schaltungsanordnung für Nachrichten-Übertragung über Fernsprechleitungen.
DE635669C (de) * 1932-11-01 1936-09-28 Friedrich Merk Telefonbau Akt Einrichtung zur Feststellung der Nummer eines anrufenden Teilnehmers in Selbstanschlussverbindungssystemen

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2597007A (en) * 1942-03-31 1952-05-20 Int Standard Electric Corp Common control circuit for operating switches rearward to calling line
US2621256A (en) * 1949-07-08 1952-12-09 Automatic Elect Lab Calling line identification apparatus
US2904635A (en) * 1950-03-02 1959-09-15 Siemens Ag Allocation of outgoing lines in automatic telecommunication systems
CN105545879A (zh) * 2015-12-04 2016-05-04 江西飞尚科技有限公司 一种基于单片机实现电磁换向阀控制器
CN105545881A (zh) * 2015-12-04 2016-05-04 江西飞尚科技有限公司 一种基于智能液压控制系统

Also Published As

Publication number Publication date
DE733911C (de) 1943-04-14
FR828570A (fr) 1938-05-20
GB484568A (en) 1938-05-02
GB484658A (en) 1938-05-02
NL56018C (xx)
NL56019C (xx)
GB484649A (en) 1938-05-02
DE887525C (de) 1953-08-24

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