US1330483A - Telephone-exchange system - Google Patents

Description

A. E. LUNDELL AND F. A. STEARN.

E TELEPHONE EXCHANGE SYSTEM.

A. E. LUNDLLAND F. A..STEARN,

TELEPHONE EXCHANGE SYSTEM.

VAPPLICATION lFILED OCT. 8| 1917.V

Patented r Feb. 10,1920.-

3 SHEETS-SHEET 2.

/n ven/ars: A/ef? E. l ande# Han/32% A. Sfar/r1 UUE .N mi

by A/fhf.

A. E. LUNDELL AND F. A. STEARN. TELEPHONE EXCHANGE sYsEM.

APPLICATION FILED OCT. 8, 19|?- Patented Feb. 10, 1920.

3 SHEETS-SHEET 3- NITED sTATEs PATENT onirica.

ALBEN E. LUNDELL, 0F NEW YORK, NWY., AND FRANKLIN A. STEARN, OF PATERSON, NEW JERSEY, A'SSIGNORS TO WESTERN ELECTRIC COMPANY, INCORPORATED, 0F NEW YORK, N. Y., A CORPORATION 0F NEW YORK.

TELEPHONE-excitait@ sYsTin/r.V

Specification of Letters Patent. Patented Feb. 10, 1920.

Application filed October S, 1917. Serial No. 195,356.

which the following is a full, clear, concise,

and exact description. l

This invention relates to telephone -exchange systems, and more particularly to improvements in systemsA vemploying machine switching.

The ob `ect of this invention is to provide the hunt for an-idle means for continuing trunk if all the trun is of a group normally associated with a selector switch are busy at the time that the hunting operation takes place.

According to a feature of this invention the hunting selector switch after having passed over all the trunks leading directly to selector switches for thc further extension of a line, passes to an idle overow trunk.

Associated with each of l these overflow' trunks there isa rotatable switch which is capable of hunting over an equivalent group of trunks continuously until an `idle trunk is found.

In the drawings, Figure 1 represents a calling subscribers line, an operators connecting circuit and a selectorswitch; Fig. 2

(to be placed to the right of Fig. l) a sequence switch arranged to seize an idle connector switch to extend a call to a called subscribers line; and Fig. 3 (to be placed below Fig. 1) anoperators controlling apparatus by means of which the selector and connector switches may be set. ,4 Y l The selector and sequence switches and the controlling apparatus therefor will notk be disclosed in full in the following description of this system, switches of this type being wellknown inthe art. A complete description of such switches may be had from 'a Patent No. 1,168,319, patentedmJanuary 8, 1916,to A. E A'Lundell. A

A The calling subscriber at station 100, desiring to obtain a connection with a suby `sc'riber at station l200, removes his receiver from the switchhook, closing thus a circuit for line relay LR, which lights a calling signal lamp CL. `The operator, noticing lamp GL lighted, inserts a pluglOl into a jack 102 in which the calling line terminates, whereupon a circuit is closed from grounded` batterythrough the winding of cut-oli relay CR, the sleeve contacts of jack 102 and plug 101, and the winding of a relay 103 to ground. Relay 103 closes a circuit 'from ground through its armature and front contact, a contactr104 andthe power magnet of a sequence switch 105 to grounded battery. Under thecontrol of anormal spring 106,

sequence switch 105 is movedout ofposim tion 1 into position 2'.' A circuit is now closed from ground through sequence switch 'contact 107, conductor 108, a contact 300 of a sequence switch 301, and the winding of arelay 302 to grounded battery. Relay'302 becomes energized and closes a circuit from ground through its left-hand armature and front. contact, a contact 303 and the power lmagnet of the sequence switch 301 to grounded battery. Under the Control of a normal spring 304, sequence switch 301 is moved out of position 1 into position 3. Relay 302 does not become'de'nergized when sequence switch 301 leaves position 1, acircuit being yclosed from grounded battery through the winding of this relay, sequence switch contact 305, the right-hand armature and liront contact of relay 302, conductor 306 and contact 109 of sequence switch 105, to ground.

v The operator by depressing her listening key 110, connects her telephone set 111into telephonie yassociation with the calling subscriber, and, in accordance with instructions received from vthe subscriber, she adjusts her controlling apparatus. Only two rows of keys are shown in Fig. 3, as it is thought suiiicient forA the purpose of the present invention. lIt will be obvious to those skilled in the art that the` switches used will be set in accordance with ra plurality of digits in order to extend the calling line toward the called line and that for this purpose a plurality of rows of keys must be yprovided at the operators position. Supposing, however, that thel called subscribers line may be seized by causing selector switch 130 to take three steps, the operator will depress key 310 and similar keys for controlling connector switches and a start-key 312. A circuit is established from ground through the contact of key 312, a

- contact 313, and the power magnet of se- `quence switch 301 to grounded battery, Jfor moving this sequence switch into position 4.

A circuit is then closed from grounded battery through the windingof relay 113, sequence switch contact 114, conductor 115, the outer armature and back contact of the upper counting relay O, the winding of a stepping relay 315, sequence switch contact 314, conductor 316, and a sequence switch contact 116 to ground. Relays 113 and 3 15 become energized. Relay 113 closes a circuit from ground through its, right-hand armature and front contact, a sequence switch contact 117, conductor 118, and the power magnet f the sequence switch 105 to grounded battery, for moving this sequence switchinto position 3. Relay 113 remains energized upon the opening of contact 114, due to the closure o'l' a substitute path through the left-hand armature and front contact of this relay, and a sequence switch contact 119.

Upon the energization of relay 315, a circuit is closed from ground through the front Contact and armature of this relay, asequence switch contact 317 conductor 318, the con` i tact of the key 310, conductor 322, the armature and back contact of the upper counting relay 2 and the winding of the lowel1 counting relay 2 to grounded battery. The lower counting relay 2 closes a circuit Jfrom ground through sequence switch contactv 320, conductor 321, the armature and front Contact of the lower counting relay 2, andthe windings of the upper and lower counting relays 2 to grounded battery. The upper counting relay 2, however, can not become energized due tothe closure of a short circuit around c its winding from ground through sequence switch contact 317, to ground through the Y armature and front contact of stepping re- 128 is moved in an upward direction, the

wipers 124, 125, 126 wiping over a terminal bank 129 and the commutator brushes 127,

128 over conducting and insulated segments f of a commutator plate 112..v Vhen the com- Amutator brush 128 engages a conducting segment 131, it connects ground `through this segment, a conductor 132, sequence switch contact 133 and 119 to relay 113,thus shunting out relay 315. Relay 315 opens at v. renergization of relay 315, which again ,con-

vthrough sequence yswitch contact 324, the

its front contact the short circuit of the upper counting relay 2, whereupon.V this counting relay becomes energized and connects conductor 322, through its armature and front contact, the armature and back contact of the upper counting relay 1, the winding pf the lower counting relay 1, and conductor 323, to grounded battery. The lower counting relay 1 connects now the upper counting relay 1 .into circuit. This relay, however, can not become energized due to the fact that commutator brush 128 moved `in the meantime into engagement with an insulated segment 134, permitting thus the nects ground to conductory 322.

The operation of the counting relays continues in substantially the same manner until the selector 130 has-been moved upward by three steps and the upper counting k.relay O has become energized. This counting relay opens, at its outer armature, the fundamental circuit including relays 315 and` 113, and closes a circuit from ground vinner armature and front contact of .the upper counting relay O and the power magnet of sequence switch 301 to grounded battery, yfor moving .this sequence switch into position 6. When the sequence switch leaves f `position 4, allthe counting relays which have been locked up become denergized.

Relay 113, upon denergization, opens the circuitof magnet 120. and closes a circuit from ground, through its right-hand armature and back contact, sequence switch contact 135, conductor 118, and the power magnet of sequence switch to grounded battery, for moving this sequence switchout ofposition 3 and into position 6.

circuit is now closed from. ground through sequence switch contacts 136 and 137, and the left-hand winding of a relay 138, to grounded battery.

The energization of relay v138 closes a cir- 110 cuit from ground, outer right-hand armature and front contact of this relay, sequence switch contact 140,*conductor 1.18 andthe power magnet of sequence switch 105 to Vgrounded battery, whereupon the sequence n.5

switch will be moved into position 7. Vhen the sequence switch 105 leaves position 6, the circuit above traced for relay 138 is opened at contact 136, butthis relay remains energized due tothe closureof a circuit from grounded battery, right-hand winding of relay 138, inner right-hand armaturel and ront contact vof this relay, conductor 152,

brush 126, to ground over the test conductor of the trunk with which brush 1.26is in engagement, provided this trunkis busy. 1n position 7 a circuit is completed for updrive magnet 120, ifrelay 138 is energized, from ground, battery, winding of the magnet, contact 145, outer armature and front contact of relay 138 to ground, thus causing the movement of the selector onto the terminals of another trunk.

Let us suppose that all the trunk lines extending direct to final selector switches in the third group of contacts of the bank 129 are busy, that is to say, ground is to be lay 138 becomes denergized and opens the circuit of magnet 120, thus arresting the brush rod 123. Relay 138 closes a circuit from ground through its outer right-hand armature and back contact, sequence switch contact 146, conductor 118 and the power magnet of sequence switch 105 to grounded battery for driving this sequence switch into position l1.

In position 11 of sequence switch 105, a vcircuit is completed from ground, contact 116, conductor 316, contact 151, brush 125, conductor '203, lower armature and back contact of relay 205, left-hand armature and back contact of relay 206, left-hand winding of relay 207 to grounded battery. Relay 207 completes circuit from grounded battery, winding of relay 208, right-hand armature and back contact of relay 206, left-hand armature and front contact of relay 207 to ground. Relay 208 completes a locking circuit for itself fromgrounded battery, winding of relay 208, inner left hand armature and front contact of this relay," conductor 209, terminal 139, brush 126, conductor 152, inner right-hand armatureL and back contact of relay 138, contact 153 to ground. Relay 208 closes a circuit from grounded battery, winding of relay 206, outer left-hand armature and front contact of relay 208, lower armature and Yback contact of relay 205 to ground over conductor 203.

The sequence switch 225 does not have a definite normal position, but remains in engagement with the last trunk to which 1t extended a call. When this trunk becomes idle and is later seized by a selector switch similar to 130, ground will be placed upon the test wire 211 through contact similar to 153 at this selector switch. Therefore when relays 208 and 207 become energized in the manner above described a locking circuit for relay 207 is completed from grounded battery right-hand winding and right armature and front contact of this relay, outer right-hand armature and front contact of relay 208, contact 1, 2, 3, 4, 5, 6, 7 or 8 of sequence switch 225, test conductor 211 to ground. This locking circuit prevents the denergizat-ion of relay 207 when vrelay 206 becomes energized in the manner above described. Relay 206 therefore completes a circuit from grounded battery, winding of power magnet of sequence switch 225, right-hand armature and front contact of relay 206, left-hand armature and front contact of relay 207 to ground.

This circuit causes the sequence switch to move into its next position wherein the above operation will again be performed, provided the trunk there encountered is busy. While the sequence switch is moving from one position to the next, a circuit is completed through the left-hand winding of relay 207 in order to maintain this relay energized. This may be traced from grounded battery left-hand winding of relay 207, left-hand armature and front contact of relay 206, contact 214, left hand armature and front Contact of relay 207 to ground.

We will assume that when the sequence switch 225 reaches the seventh position, it finds an idle trunk. The circuit through the right-hand winding of relay 207 will then be opened, since no ground will be found upon the test conductor 211. Relay 207 therefore denergizes and opens the circuit for the motor magnet of the sequence switch. Relay 207 also closes a circuit from lgrounded battery, winding of relay 205, inner right-hand armature and front contact of relay 208, left-hand armature and back contact of relay 207 to ground.

Relay 205 opens the circuit of relay 206 and extends the conductors 202 and? 203 through to the connector switch wassociated with the selected idle trunk. Relay 205 also by attracting its upper armature corn- -pletes the fundamental circuit through to the stepping relay (not shown) at the con nector switch. This stepping relay will be controlled in the well known manner to operate the connector to complete the connection to the called subscriber substation 200. Since this operation does not form part of this invention, it is believed that a complete description of the operation is unnecessary. y y

The subscribers desiring disconnection restore their receivers to the switchhoolrs, causing thus, in the well-known manner, the actuation of supervisory signals 160 and 161. The operator noticing the actuation of these sign als removes plug from jack 102, whereupon relays CR and 103 become denergized, the -latter closing a circuit from ground through its armature and back contact, and a contact 162 and the power magnet of sequence switch 105 to grounded battery, whereupon this sequence switch is moved into position 18. In position 18 of the sequence switch, a circuit is closed from grounded battery, through the winding of magnet 168 and a sequence switch contact L 164 toy ground. Magnet 163 presses, by means of its armature 165, the brush rod 123 against a roller 166 constantly rotating in the direction indicated by the arrow, andthe brush ro d with the wipers and brushes mounted thereon is lowered. lVhen the brush rod reaches its normal position, a circuit is closed from ground, through commutator brush 128, a conducting segment 167, conductor 168, a contact 169conductor 118, and the power magnet of sequence switch 105 to grounded battery, yfor moving this sequence switch out of posit-ion 18 into position 1. Vhen the sequence switch leaves position 18, magnet 163 becomes denergized.

As soon as sequence switch 105 leaves position 16, the contact 153 is opened, causing the denergization of relay 208, which in turn opensthe circuit of relay 205.

Relay 208 removes ground from test conductor Q11, thus causing the releasevof the connector switch in the well known manner.

If the sequence switch 225 had been in position 7 at the time the overflow trunk was seized by the selector 130 no ground would have been foundupon the test wire 211 for completing the locking circuit of relay :207 through its right-hand winding and armature and therefore when the relay 206 is energized in the manner above described the relay 207 denergizes, since contact 214 is yopen in position 7. Relay 207 is so constructed that it will release its armatures before the circuit of the power magnet of sequence switch 225 is completed through the front contact of relay 206. vThe sequence switch will therefore remain in position 7 lhat is claimed is:

1. In an automatic telephone system, incoming lines, groups of trunks, overflow trunks associated with each group of trunks, a hunting switch associated with each overflow trunk, a group of trunks terminating at each of said switches, said switches being arranged to be normally in engagement with any one of the .said last mentioned trunks terminating thereat, means for connecting an incoming line to an overflow trunk, means actuated'by said connection for operating the switch associated with said overflow trunk to extend the connection to the trunk with which it is in engagement if said trunk is idle or to start hunting for an idle trunk if said trunk is busy, and means for stopping .said switch upon the` first. idle trunk eneased- 2. In an automatic telephone system, incoming lines, groups of trunks, overflow trunks associated with each groupv of trunks, a hunting switch associated with each` overflow trunk, said switches having no definite normal positions, a group of trunks terminating at each of said switches, means for connecting an incoming line to an overflow trunk, means actuated by said connection for operating the switch associated with said overow trunk to extend thev incoming line to an idle trunk.

3. In an automatic telephone system, incoming lines, groups of trunks, overflow trunks associated with each group kof' trunks, a hunting switch associated with each overflow trunk, a group of trunks terminating at each of said switches, each of said switches having no definite normal positions and being arranged to be normally in engagement with any one of the trunks terminating thereat, means for connecting an incoming line to an overflow trunk, means actuated by said connection for operating the switch associated with said overliow trunk to extend the connection to the trunk with which it is in engagement if said trunk is idle or to start hunting for an idle trunk if said trunk is busy, and means for stopping said switches upon the first idle trunk engaged.

Ll. In a telephone system, a line, a selective switchv for extending said line, groups of trunks terminating in said switch, overflow trunks associated with each said group, means for selectively setting said switch in association with any of said groups, means responsive to the busy condition of all trunks constituting said selected group for setting said switch on an idle -oneof said overflow trunks, an equivalent group of trunks associated with each overflow trunk, a unidirectional rotatable selective switch having no normal position for automatically ALBEN E. LUNDELLj FRANKLIN A. STEARN.

Images