US1606199A - Telephone-exchange system - Google Patents

Description

'R. S. WILBUR TELEPHONE EXCHANGE SYSTEM Filed Sept. 18 1923 2 Sheets-Sheet 1 Ra l I/Mbu/ Nov. 9, 1926. 1,606,199

. R. S. .WILBUR TELEPHONE EXCHANGE SYSTEM I Filed Sept. 18, 1925 2 Sheets-Sheet 2 //7 Van for:

Ray 5. Wilbur by -M /wy Patented Nov. 9, 1926.

RAY s. WILBUB, or LYNDHUBST, NnwJEnsnY, Ass enoaro wnsrnnnmnormo COMPANY, INCORPORATED, OF YORK, N. Y A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

' Application filed September 18,1923. SerialN-o. 663,369.

This invention relates to telephone exchange systems .and more particularly to-a system in which connections are established between telephone lines by means of auto.- matic switching apparatus.

The object of this invention is toprovide an improved impulse circuit for set-ting the automatic selector switches in systems of this character. i

The invention will be more readily understood by referring to the accompanying drawings, Figs. 1 and 2 and the more detailed description which follows:

In accordance with this invention a source of alternating current, preferably within the voice range, i's provided at the central office, which upon the initiation of a call on anytelephone line is connected in a circuit including the impulse dial at the substation; An alternating'current relay at the central office, which responds to the impulses produced by the dial, repeats these impulses into a chrect current circuit including-a direct current impulse relay which controls the setting of the (numerical) switches t connect with the desired line.

Fig. 1 represents the called station and the usual train of selector switches and a portion of a trunk circuit through which these switches are approached. Fig. 2'16PIB- sents the remainder of this trunk circuit, a line finder connected thereto and a calling subscribers station, also a trunk finder, and an impulse repeater connected thereto. This invention may be applied to any telephone system employing automatic or mechanical switching devices, but for purposes of explanation in this application it is applied to, and described in connect-ion with, the well known Strowger system such as is described in the patent to A. H. Blessing, No. 1,176,269, March 21, 1916. The selector switches S and S Fig. 1, may be of the type of the switch shown at E and the connector C of the type of the switch I, both shown in Fig. 2 of the Blessing patent. The apparatus shown at B Fig. 1, is part of the repeater circuit and will be described hereinafter in greater detail. r

In general, the system functions in the following manner.

One station desiring to communicate with another removes the receiver from the switchhook thus causing certain circuits to function and connect acombined repeater and se lector circuit to the calling line. The repeater circuit which is'supplied with alternating current preferably of a frequency and magnitude within the voice range is capable of being associated wvith a selector switch of the well known Strowgerv type. When the calling station dials, the repeater responding to the impulses of alternating current produced, reproduces the train of im pulsesito energize the selector switch causing it tostep to the proper level, trunk hunt, and connect with an idle selector switchin the succeeding trunk group in the manner well known in the art. The repeater now controls the operation of the succeeding selector switches of the train in the same manner, until the connection is extended to the desired called line when the impulse circuit is opened and the talking circuit is established. lVhen the conversationv is completed and the callingstation receiver is replaced on the switch-hook the circuit is released and the switches are restored to normal.

Having now outlined the system and its operation in a general manner, the method of establishing a connection between stations 200 and 100,'which may be in the same or separate exchanges depending upon the code number of the station called, will be de-' scribedin detail.

Regular call.

- When the, receiver at station 200 (Fig. 2) is removed from the switchhook line relay 204 operates. Relay 210 then operates over a circuit including a contact of relay 2&1 and brush 208 of the line finder switch LF. It should be understood that the brushes 205 to 208 inclusive move together under control of the stepping magnet 209 in-the manner hereinafter described, and that these brushes in normal position rest upon the normal terminals as shown in Fig. 2. It should be noted that the conductor 251 is connected. to the front contact'of all other line relays in the same group as the line relay 204 so that the circuit to' operate relay 210 will be closed regardless of which particular line relay in the group is operated. It should also be noted that the back contact of each line'relay is connected to a terminal in the arc with which the brush 208 is associated, Relay 210 in operating closes a circuit to operate the stepping magnet 209 by way of brush 208 and the front contact of relay 204. The stepping magnet 209 opens its own operating path and releases, causing the brushes 205 to 208 inclusive of th'eswitch LF to 10-.

' leasing during hunting untilthe brushes are centered on the terminals of the calling line. Assuming-that the brushes 205 to 208 are now resting upon a non-calling line, its associated line relay Will not be operated and will supply a ground to again operate the stepping magnet 209 and advance the brushes of the switch LF to the terminals of the next line in the bank, when the stepping magnet 209 releases. Assuming these terminals are associated with the station 200 the line relay 204 which is operated will prevent ground being supplied to the brush 208, hence the relay 210 will release thus preventing the stepping magnet 209 from reoperating. l telay 210, in releasing, closes a circuit by way of brush 207, to operate relays 203 and 241 in series, thus releasing the line relay 204 and preventing the relay 2 10 from reoperating.

\Vith the brushes 205 and 206 of the line finder switch LF resting upon theterminals associated with station 200, the line is ex tended to operate relay 111 of the selector S under control of relays 110, 11.4, and 117, by way of leads 227 and 228. Relay 111 operates relay 112, and the latter in turn operates relay 113 both over obvious circuits. Relay 241 operated, closes a circuitto operate relay 222 under control of relays 223, 241, 242, and brush 218 of the trunk finder TF in its normal position. Relay 222 operated, closes a circuit to operate the stepping magnet 219 under control of brush 218, and relays 241 and 242. It should be noted that the lead 252 connected to one of the forward contacts of relay 241 is strapped to one of the forward contacts of all similar relays in the group of trunk finder circuits, so that relay 222 and stepping magnet 219 will operate whenever relay 241 or some other similar relay operates. It should also be noted that with relay 241 operated, ground will be connected to every terminal of the are associated with brush 218 except the terminal corresponding to the trunk 227, 228 connected to line finder LF.

The stepping magnet 219 operated, opens its own operating circuit and releases, thus advancing the brushes 211 to 218 inclusive of the trunk finder switch TF from the normal position to the terminals associated with the first line finder in the group.

Since this is not the line finder circuit sought, ground will be connected to brush 21.8 by Way of the relays in the first line finder circuit corresponding to relays 241 and 242, hence the stepping magnet 2.19 will reoperate and upon releasing advance the brushes 21 1 to 218 inclusive of the trunl;

which terminal is free from ground, relay 222 will release thus closing a circuit controlled by relays 222 and 241 by way ol? brush 217 to operate relays and 242 in series. The operation of'relay 242 causes the line finder circuit to test busy to all other trunk finder circuits, the operation of relay 223 prevents relay 222 from 'reoperating, and the release of relay 2 2 prevents the stepping magnet 219 fromadvancing the brushes oifthe terminals associated with the line finder circuit LF. T he operation of relay 223 operates relay 233 over an obvious circuit and closes parallel circuits to operate relays 114 and 117 of the repeater R (Fig. 1), by Way of lead 226 and brush 214. Re lay 233 operatedpoperates relay 232 over an obvious circuit, and relay 114 prepares the impulse circuit under control of armature 125 of relay 115 thus preventing relay 111 from releasing when relay 117 operates'and prepares the operating circuit for relay 23 3 hereinafter described. I ,Relay 233 op'erated, closes a circuit to the source of alternating current supply 234 operate relay 236 as follows: 234, 216, 119, 120, 121, 227, 205, 202, 201, 200, 12, 206, 228, 122, 123, 124., 230, 215, 230 to ground. 'Relay 117 operated closes a circuit to ground to operate relay 116 under control of relay 241, by way of lead 225; Relay 116 operated locks to ground under control of relay 241.

The circuit is now. ready to receive the first series of impulsesproduced by the substation dial'201. The dial201 is now operated and released and as it returns to normal the loop of station 200 is momentarily opened by the impulse contacts (not shown) of the dial 201. Relay 236 which 1s a very fast alternating current relay releases and closes its contacts 235, thereby completing the circuit to operate relay 237 under control of relays 232 and 223,' and a parallel circuit to operate relay 115 by way ofl- eads 126 and 229 and brush 213, also under control of relays 232 and 223.

Relay 237 closes an obvious circuit to operate the stepping magnet'221 of the trunk finder T1 sequenceswitch which includes brushes 243 and 220, whilerelay 115 being operated opens the holding circuit of the impulse relay 111 which closes the usual circuit (not shown) to cause the selector to step in the usual manner, well known in the 111. Each time relay 236 releases, relay 115 operates and relay 111 releases, thus repeating the impulse from the dial circuit to the impulse relay 111 of the selector S. When the impulses corresponding to the first digit cease relays 115 and 237 both release, the former thus holding impulse relay 111 operated I as before, While the latter releases stepping magnet 221 thus advancing the brushes 238 and 243 to the next terminal in their respective arcs. At the end of the train of impulses, the selector S hunts in a manner particularly shown and described in said patent, and selects an idle selector which we will assume to be the selector S Relay 110 now operates, releasing relays 111 and 112 and extending the impulse path controlled by relay 115 by way o f brushes 109 and the terminals 108 to the impulse relay (not shown) of the selector S and the holding ground previously supplied by relay 112 to operaterelay 113, is replaced by a ground connected to lead 127 in the man ner shown in said patent. The dial 201 is again operated and released for the next digit and relays 236., 115 and 237, and stepping magnet 221, function as previously described. Relay 115 now controls the circuit of the impulserelay (not shown) of the selector S causing the selector S to function in a similar manner to the selector S.

At the end of this train of impulses relays 236, 237, and 115, stepping magnet 221, and brush 220, function in the same manner as at the end of the first impulse train, and we will assume that the impulse circuit is extended to the connector C by way ofthe brushes 107 and terminals 106, in which case relays 104: and 105 will operate, and the final impulsing circuit to relay 10 1 is now established under control of relay 115. The holding ground is now supplied from the connector relay 105 in the manner shown in said patent. v

When the third digit is dialed at station 200, relay 237 operates the stepping magnet 221 which upon releasing steps the brush 220 to the next terminal of the are 238, and after the final digit is dialed the brush 220 comes to rest upon the terminal 239 of arc 238.1 During these operations anduntil disconnection takes place the ground to keep relay 113 operated is supplied by relay 105.

\Ve will assume that't'he brushes 102 finally come 'to rest upon the "terminals 1010f the called line 100, that relay 103 operates, the called line is signalled, and the party answersby removing the receiver from the switchhookQall of which is shown and de scribed in' detail in said patent.

When the brush 220 of the stepping mag net 221 comes torest upon the terminal 239 of are 238, an obvious circuit to operate the stepping magnet 219 is closed by way of brush 212 and lead 246, and'the brushes 211 to 218 inclusive are restored to the normal position of the trunk finder switch 'LF. hen brush 217 steps off terminal 247 the I circuit through relays 242 and 223 is opened, releasing these 'relays. Relay 223 released, releases relays 115, 2 33 and 237. Relay 233 releases relays'232 and 236. When brush 21 1 steps off terminal 248, the circuit through relays 114: and 117 isopened, releasing these relays and establishing the trans mission circuit, by extending leads 227 and 228 through to the brushes 102 of the con- I nector C, thence to the called station 100. ith the trunk finder switch TF in its normal position a circuit is closed to operate the stepping magnet 221 by Way of brushes 243 and 211 to ground on the terminal 24 1. I thus restoring this switch to normal.

Disconnection.

\Vhen the conversation is completed the receiver is replaced on the switchhook of station 200 thus releasing relay 104, which 9 in turn releases relay 105. Relay 105 released removes, the holding circuit for cut oil relay 103, and the holding relays of the switches, and releases relays and 113. Relay 113 closes a circuit to operate the 105 step-ping magnet 209 of theline finder switch LF under control of relays 114 and 116 by way of lead'224.

Stepping magnet, 209 operated, opens its own operating circuit and releases, thus step- 110 ping thebrushes-205 to 208 of the switch LF from the terminals associated with the line 200. When the brush 207 steps 01]. the terminal 24:9, cut'ofi' relay 203 and relay 241 re lease, the former thus restoring line 200 to normal, and the latter closing a circuit to operate relay 210 by way of brush 208 and the terminal 250 which will be grounded under control of the line relay (not shown) associated with the line connected to terminal 250. The stepping magnet 209 'reoperates and releases thus stepping the brushes 205 to 208 of the switch LF to the terminals of the next line otthe group. This cycle of operations continues until brushes 205 to 208 either find another calling line, in which case the new call is established in the manner hereinbefore described, or the switch returns to normal, thati's, the brushes of the line finder LF may be constructed as shown 130 Gall abandoned before calling Zine is found.

Should the receiver at the station 200 be removed from the switchhook long enough for the stepping magnet 209 to operate once, the brushes 205 to 208 inclusive of the switch 'LF will step to the terminals of the first line of the group. The release of relay 204 will cause the line 200 to test busy, and relay 210 will remain operated, and the stepping magnet 209 will step until the brushes 205 to 208 of the switch LF return to normal.

Gall abandoned before a repeater circa .525 found.

WVhen the receiver at station 200 is removed from the switchhook the stepping magnet 209 will step the brushes 205 to 208 inclusive to the terminals of the calling line, and relays 111 and 241 will operate in the manner previously described under Regular call. The stepping magnet 219 of the switch TF also will function, and relays 242 and 223will operate in the manner previously described. When the call is abandoned, relay 111 of the selector S will release, releasing relay 112, which will release relay 113. A circuit is now closed'to operate the stepping magnet 209 of the switch LF under control of relays 113 and 242, by way of leads 118 and 245. The-stepping magnet 209 restores the line finder switch LF to normal in the manner previously described under Disconnection. Relay 222 reoperates wheni'elays 223 and 241 release, and the circuit to operate the stepping magnet 219 and restore the trunk finder switch TF to normal is closed by way of brush 218.

Gall abandoned before dialin is commenced.

If the call is abandoned after the repeater circuit is found but before dialing, the line finder and trunk finder switches are restored to normal in the manner described in the last paragraph.

Gall abandoned daring dialing.

,by way of lead 224, thus releasing relays 241 and 203 and restoring the line finder switch operate the stepping magnet 219 and re store the trunk finder switch TF to normal under control of relays 222, 241 and 242 by way of brush CaZZ abandoned after dialing is completed.

The circuit is restored to normal in the manner previously described under Regw lar call.

lVhat is claimed is: p r

1. Atelephone system comprising a calling line equipped with a calling device, a called line, automatic switching apparatus at an intermediate point for interconnecting the calling and called lines, an alternating current source at an intermediate point, repeating means controlled by'impulses produced by interruptions oi current from said source by said calling device for transmitting for each alternating current impulse received by said repeating means a'direct current impulse and means for 'settingsaid automatic switching apparatus under control of said direct currentimpulses. V

2. A telephone system comprising a calling line equipped with a calling device, a called line, automatic switching apparatus at an intermediate point for interconnecting the calling and called lines, an alternating current source at an intermediate. point, means for connecting said source to the calling line operated'when the calling line is taken for use, repeating means controlledby impulses produced by interruptions of current from said source by said calling device for transmitting for each alternating current impulse received by said repeating means a direct current impulse and means "for setting said automatic switching apparatus under control of said direct current impulses.

8. A telephone system comprising a calling line equipped with a calling device, it called line, automatic switching apparatus at an intermediate point for interconnect-- ingv the calling and called line, a high frequency alternating current source at an in termediate point, repeating means controlled by impulses produced by interruptions of current from said source by said calling device for transmitting for each alternating current impulse received by said repeating means a direct current impulse and means for setting said automatic switch apparatus under control of said direct current impulses.

4. In a telephone system, acentral oilice,

telephone lines terminating thereat, calling dials at the stations of said lines, selectors, non-numerical switches for extending calling lines to said selectors, a trunk finder,

means actuated upon the initiation of a call for setting the finder in motion to connect with a selector taken for use by a calling line, a source of alternating current and an alternating current impulse relay associated with said trunk finder, an impulse circuit for said relay including said source, said trunk finder, said non-numerical switch and the calling line including the dial, and a second impulse circuit for controlling said selectors and including a source of direct current and a direct current impulse relay said secondcircuit being directly controlled by the alternating current relay so that for each alternating current impulse as it is received a corresponding direct current impulse is produced for the corresponding operation of said direct current relay.

5. In a telephone system, a central olfice, telephone lines terminating thereat,- calling dials at the stations of said lines, selectors and connectors, non-numerical switches for extending calling lines to said selectors, a trunk finder, means actuated upon the initiation of a call for setting the finder in mo tion to connect with a selector taken for use by a-calling line, a source of alternating current and an alternating current impulse relay associated with said trunk finder, an impulse circuit for said relay including said source, said trunk finder, said non-numerical switch and the calling line including its dial, a second impulse circuit for controlling said selectors and connector and including a source of directcurrent and a direct current lmpulse relay, said second circuit being directly controlled by the alternating current relay so that for each alternating current impulse received a corresponding direct current impulse is produced for the correspo-nding portion of said current relay and means for restoring said trunk finder upon the selection of the'called line, whereby it reverts to common use.

6. In a telephone system, a central oifice, a telephone line, a selector at the central oflice for association with said line, a source of high frequency current and an alternating current relay at said central office, an interrupter in said telephone line, an impulse circuit including said source, said relay, said interrupter and the conductors of said line, a second circuit into which impulses are repeated by said alternating current relay and including a source of direct current, an impulse relay for setting said selector and a contact of said alternating current relay and a switching means for disconnecting said sources of high frequency current and alternating current responsive to the reception of a certain number of series of impulses and means operative in response to such disconnection for connecting the selector with said conductors.

In witness whereof, I hereunto subscribe my name this 4th day of September A. D., p

RAY S. WILBUR.

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