US1644727A

US1644727A - By-pass selector circuit

Info

Publication number: US1644727A
Application number: US107755A
Authority: US
Inventors: Jacobsen Emil
Original assignee: American Telephone and Telegraph Co Inc
Current assignee: AT&T Corp
Priority date: 1926-05-08
Filing date: 1926-05-08
Publication date: 1927-10-11
Anticipated expiration: 1944-10-11

Description

Oct. 1 192 7 E. JACOBSEN BYPASS SELECTOR CIRCUIT- I etl Filed May 1926 I 3 Sheets-She /7V/7/0/. [/m/ Jaaafise/Z Y Oct. 1111927.

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BE Q E 1 E a I 0 I Q C 1 g-l-H l V R E l H Patented Oct. 11, 1927.

UNIT-E" SYS- OFFICE.

EMIL JACOBSEN. F PLANDOME, NEW! YORK, ASSIGNGB TO AMERICAN TELEPHONE AND TELEGRAPH COMPANY; A CORPORATION OF NEW YORK.

BY PASS SELECTOR CIRCUIT.

Application filed May'8, 1926. Serial No. 107,755.

lect a main office trunk and selector on all.

calls whether to a main office or a satellite office. lVhen the c all'was for a satellite ofan extra digit was dialed vhicbi caused the repeater to release the main ofiice trunk and complete the call over a local trunk.

eater after releasing the main oflice trunk hunted for an idle trunk to a tribu-,

tary office with the same set of brushes which were originally used in connecting to the main office trunk. I

in this invention the same end is attained with the use of a repeater having two sets of banks and brushes trunks to the main office being connected to one set and trunks to a local oliice being connected to the other.

I lso it is not necessary to dial an extra 't in ord r to complete a call to a local the main oflice trunk and switch to the .5 set of brushes which are connected to the local otlice, by external. means. ad-

35 vantages will be pointed out in the ioilowinc" description and claims.

he system disclosing the invention in one of its narrow aspects consists of a calling line in a satellite or local oilice, a by-pass se- 40 lector and repeater circuit, a trunk to a main office, a main otlice selector and a trunk from the by-pass selector to a local selector in a local or satellite office. The bypass selector is the principal feature o this invention bein used for by-passing a call from a. local suscriber to a local subscriber without the necessity of going through a main office. WVhen a call is initiated whether for a local or main oitlce subscriber, it is routed to a main office selector. Certain levels of this selector have battery and ground connected thereto and these levels are reached by the dialing of certain numbers which are assigned to local office subscribers.

' The battery and ground connected tothese riber as the repeater is caused to relevels operates a polarized relay in the bypass selector which causes the release of the main office second selector switchand initiates the selection of a'trunk to aisecond selector in a tributary ofiice- Thisleaves the main office selector'free for useby other bypass selectors. V

The number of digits dialed is the same for a. call to a main oflice as it is for a call to a local otlice, that is, if it takes three digitsto complete a connection to a subscribers station in a main oilice, it will be necessary to dial three digits to reach the subscriber in a local oilice'. A. more clear. conception may be obtained of the objects andoperation of this invention. frointhe following descrip tion in which: J

Figure 1 shows the bypass selector S with two sets of brushes, the upper set of which are'connected to a selector in the main oflice and the lower connected to a selector in a tributary office.

Fig. 2 shows a second selector in a main office, the banksof which are shown connected. to a subscribers station in the 'main office and other banks to which battery and ground are connected for controlling the selectors. The brushes are shown in their normal position.

Fig. 3 shows a selector in a local office. v Fig. 4 is a diagrammatic representation of the system. line, B the by-pass selector, B the main office selector and C a subscribers line at the main oiiice. E is theselector in the local oflice and the line from R to E desigswitch 102 selects the bypass-selector. S in a manner well known in the art. A circuit is closed for relay 107 from ground through its right winding, right back contact of relay 108, outer left back contact of relay 106, brush and terminal 103 of line switch102, through the subscribers loop 101, line switch 102, brush and terminal 104, inner left back contact of relay 106, left back contact of relay 108 to battery through the winding of relay 107. The operation of relay 107 closes the bridge formed by the right winding of relay 11 i across. the conductors to the arcs 120 and 130. The operation of relay 107 also operates relay 109 overan obvious cir- A is a calling subscribers cuit. The operation of relay 109 connects ground from its outer left front contact to terminal 105 holding line switch 102 operated. Relay 109 also prepares in part a circuit for stepping magnet 116 and test re- My 111. If the selector brushes 120, 130

' and 140 are in contact with a busy trunk such as 205 to the main oflice, ground will be connected to brush 140 thereby closing a circuit for magnet 116 from said ground, inner-right back contact of relay 111, inner left front contact of relay 109, outer left back contact of relay. 113 to battery through the interrupter contact and winding of magnet 116. A parallel circuit is also closed from ground on the outer right back contact of relay 113, outer right front contact of relay 109, winding of relay 111, middle left back contact of relay 113 to battery through the magnet 116. The ground on are 140 acts as a shunt to'the winding of relay 111 which does not operate, but magnet 116 operates and steps brushes 120, 130 and 140 until an idle trunk is found, at which time relay 111 operates in a series circuit through the winding of magnet 116. Magnet 116, however, does not operate as tl e resistance of relay 111 is too high. The operation of relay 111 closes the talking conductors through to arcs 120 and 130 and connects ground to the brush of arc 140 thereby making the trunk test busy to all other selectors. The operation of relay 109 also closes an obvious circuit from ground on the outer right back cont-act of relay 113 through the left winding of relay 114 thereby preparing it as a polarized relay. This relay, however, does not operate at this time over its left winding.

Subscriber 101 now operates dial 121 whichopens the circuit through relay 107. The release of relay'107 does not release relay 109 as relay 109 is a slow-to-release type relay which holds up thereby closing a circuit from ground on the rightback contact of relay 107, inner right front contact of relay 109 to battery through the winding of relay 110. Relay 110 is also slow-to-release and does not release at any time during dialing. The operating of relay 110 closes a circuit from ground on the outer right back contact of relay 113, outer right front contact of relay 109, right front contact of relay 110, inner back contact of relay 114 to battery through the winding of relay 115. As the dial 121 returns to normal, relay 107 follows the dial impulses and opens and closes the circuit from battery through the left winding of relay 222, inner right back contact of relay'213, conductor 139 of trunk 205, brush and are 130, middle right front contact of relay 111, left front contact of relay 110, left front contact of relay 107, outer right front contact of relay 111, brush and arc 120, conductor 129 of trunk 205, outer left back contact of relay 213 to ground on following release of relay 222 now closes a circuit from ground on the inner left back contact of relay 213, back contact of relay 222, left front contact of relay 221, Winding of relay 220 to battery through the vertical magnet 219. During the following impulses relays 220 and 221 remain operated as they are of a slow-to-release type. The operation of vertical magnet 219 causes brushes 210, 211 and 212 to be moved upward to the desired level which contains terminals 207, 208 and 209. When these brushes leave their normal position the off normal springs 224 are closed to enable the closing in part of a circuit for relay 216 from ground on the right front contact of relay 221, front contact of relay 220, upper contact of off normal contact springs 224, to battery through the winding of relay 216. Relay 216 locks over a circuit from ground on the inner left back contact of relay 213, outer front contact of relay 216, back contact of magnet 215, upper contact of off normal contact springs 224 to battery through the winding of relay 216.

hen the dial has returned to normal af ter dialing the first digit, relay 220 releases and a circuit is closed as follows for the rotary stepping magnet 215: battery, through the winding of said magnet, inner contact of relay 216, normal contact of relay 220 to ground at the right contact of relay 221. The magnet 215 advances the

brushes

210, 211 and 212 to the first set of terminals. Magnet 215 also opens the circuit of relay 216, releasing this relay and the relay in turn opens the operating circuit of magnet 215 permitting it to release. If the first set of terminals engaged by the brushes is busy the relay 216 again operates in a circuit from battery through its winding, contacts 224, contact of magnet 215, right back contact of relay 213, brush 212 to the grounded busy terminal. Relay 216 operates closing the circuit for the magnet 215 which advances the brushes to the next set of terminals. This operation will be repeated until an idle trunk is found. A circuit is closed during the operation of magnet 215 from ground on the right front contact of relay 221, upper normal contact of the eleventh rotary position off normal contact spring 206, winding of relay 213, back contact of magnet 215, upperalternate contact of ofi normal contact spring 224 to battery through the winding of relay 216 in parallel with one from busy ground on brush 212 through the outer right back contact of relay 213 and thence over the same circuit through'the winding'of relay 213. While the brush 212 is resting on a busy terminal relay 213 is shunted but as soon as an idle terminal is found this shunt is removed and relay 213 operates and connects

conductors

129, 139 and 149 through to

brushes

210, 211 and 212. Due to the resistanceof the circuit relay 216 does not op erate in series with relay 213. 3 it will be assumed that brushes 210, 211 and 212 are resting on terminals 207, 208 and 209 from which the connection would be completed to station 201 through the third selector and connectorin a manner wellknown to the art.

As this system has to do with the switching from a main office selector to a local of ice sel ctor, an explanation of the wiring of

arcs

250, 251 and 252 will be necessary. Certain levels on the switch over i which brushes 210, 211 and 212 move are wired direct to lines in the main otfice such as line If however, the call is for a line such as 301 in a local oiiice, certain levels such as those containing

terminals

203 and 204, corresponding to the first digit of the subscrihcrs number have battery and ground connected thereto for giving a battery reversal to the bypass selector. When such a call is made, the operation of the main otlice selector switch will be difierent. After the first digit is dialed and the rotary magnet 215 is operated brushes 210, 211and 212 are caused to hunt. No ground will be found on this bank for brush 212 therefore relay 213 will operate as described above and close the

conductors

129, 139 and 149 hrough to

brushes

210, 211 and 212 which are assumed to be resting on

terminals

203 and 204. Battery and ground will be connected to these terminals and will close a circuit from battery on terminal 203, brush 210, outer left front contact of relay 213, conductor 129, are and brush 120, outer right front contact of relay 111, left front contact of relay 107 through the polarized winding of relay 114, middle right frontcontact of relay 111, are and brush 130, conductor 139, inner right front contact of relay 213 to ground on terminal 204 through brush 211. Relay 114 operates and opens the circuit through relay 115 which is slowto-release and so holds up until a circuithas been closed for operating relay 113 from ground on the outer front contact ofrelay 114, front contact of relay 115 to battery through the winding of relay 113. -Relay 113 operates and locks over an obvious circuit to ground on the outer left front contact of relay 109. The operation of relay 113 closes a circuit from battery through the winding of magnet 116, outer left front contact of relay 113 to ground through the winding of relay 106. The operation of relay 113 also opens the circuits for relays 111 and 114 and allows them torelease.

The release of relay 111 opens the holding circuit for relay 213. The release of relay 213 closes a circuit for ground on. its inner left back contact, back contact of relay 222,

left back contact of relay 221, lower alternet 116 will be operated thereby stepping.

brushes 150', 160 and 170 until an idle trunk is reached when the shunt around'relay 106 is removed allowing it to operate. Magnet 116 does not operate at this time as the resistance of relay 106 is too high. The operation of relay 106 disconnects

conductors

126 and 136 from

terminals

103 and 104 and connects

conductors

131, 132 and 133 to

terminals

103, 104 and 105 through the contacts of relay 106. When

conductors

126 and 136 are disconnected, the circuit of relay 107 is also opened allowing it to release, in

turn releasing relays

109 and 110.

Selector S is now in condition for the next digit to be dialed to the selector in the local oflice over

leads

169 and 179. A circuit 1s closed from ground through the left winding of relay 322, outer right back contact of relay 313, conductor 17 9, brush and are 17 0, conductor 132, outer left front contact of relay 106, terminal and brush-1030f line switch 102 through the subscribers loop, brush and terminal 104, inner left front contact of relay 106, conductor 131, brush and are 160, conductor 169, innerleft back contact of relay 313 to battery through the right winding of relay 322. Relay 322 follows the dial impulses in the same manner as relay 222 and the operation of the circuit is the same as that described for the selector in Fig. 2. It will be noted that the num bering of the apparatus of Fig. 3 is the same as that of Fig. 2 with the exception of the hundreds digit.

After the

brushes

310, 311 and 312 ofthe selector switch have been set ,on the termi-.

l/Vhen subscriber 301 replaces the receiver on the switchhook, the release of the switches in Fig. 3 is the same as that described for the selector in Fig. 2 when released by the by-pass selector.

What is claimed is:

1. In a telephone system, a selector hav ng a plurality of banks and a single operating mechanism, a plurality of trunks, part of said trunks being connected to part of said banks, the remainder of said trunks being connected to the remainder of said banks, means l'or setting said switch to establish a connection through one of said banks, and means in said selector for automatically releasing said switch and re-establishing said connection through another of said banks.

2. In a telephone system, a selector having a plurality of banks, sets of brushes "for cooperating with said banks, a s ngle operating mechanism for driving said brushes, a plurality of trunks toa main oihce, a plurality of trunks to a local o'l'lice, said main oflice'trunks being connected to part of said banks, said local oliice trunks being connected to the remainder of said banks and means in said selector for switching from one group of trunks to tne other.

3. In a telephone system, a repeater having two sets of terminal banks and two sets of brushes cooperating therewith, a trunk to a main office with a selector con nected thereto, a trunk to a local oi'lice, said main oilice trunkbeing connected to terminals in one set of banks, said local office trunk being connected to terminals in the remaining set 01" banks, means in said repeater for causing said repeater to switch from one trunk to the other, and means in said selector for operating said first means 4;. In a telephone system, a by-pass repeater having two sets of terminal banks, a trunk to a. main otfice with a selector connected thereto, a trunk to a local oilice, said main office trunk being connected to one set of said banks, said local otfice trunk being connected to the other set, said selector having different levels of terminals in its banks, a source of potential connected to certain of said levels which are assigned to the same designation as that of the local trunk, and means in said repeater operated by said source of potential for causing said repeater to switch to said local trunk.

5. In a telephone system, a bypass repeater having two sets of terminal banks, a trunk to a main oflice with a selector connected thereto, a trunk to a local office, said main oflice trunk connected to one set of said banks, said local oflice trunk connected to the other set, means to cause said repeater to connect with said main oifice trunk, said main oliice selector having different levels of terminals in its banks, sources of potential connected to certain 01" said levels to which are assigned the same designation as the local trunk, and a polarized relay in said repeater operated by said sources for causing said repeater to switch to said local trunk.

'6. In combinatioma repeater circuit comprising two sets of terminal banks with separate sets of brushes cooperating therewith, a main ofliee trunk connected to one set of terminal banks, a local oi'lice trunk connected to the other set of said banks, a polarized relay and means actuated over said main ollice trunk for operating said polarized relay to cause said repeater to switch from one trunk to the other.

7, In a telephone system, a main exchange and a. local exchange, a selector having a plurality of arcuate banks of contacts, wipers for engaging said contacts, a mechanism for operating all of said Wipers in a step-by-step movement, a group of trunks leading from some of said banks to the main exchange, a second group ot' trunks leading from other of said banks to the local exchange, and means in said selector for switching from one group of trunks to the other.

In testimony whereof, I have signed my name to this specification this 7th day of May 1926.

EhIIL JACOBSEN.