US2138147A - Time of day announcing system - Google Patents

Description

NOV. 29, 1938. F DRUM l 2,138,147

TIME OF DAY ANNOUNCING -SYSTEM Filed April 8, 1958 /N VE N TOR By @fom/M A TTORNEY Patented Nov. 29, 1938 UNITED STATES TIME F DAY ANNoUNoINGsYsTEM George Frederick Drum, Millburn, N. J., assignor to American Telephone and Telegraph Company, a corporation of New York Application April 8, 1938,.Serial No. 201,006

8 Claims.

This invention relates to telephone exchange systems and more particularly to circuits for enabling the extension of time-of-day service fromv time-of-day service bureaus serving local exchange areas to outlying toll areas.

Time-oi-day service has heretofore been supplied in' large metropolitan areas from time bureaus therein accessib-le from subscribers lines terminating in ofces of such areas over special `trunk networks. Thus, when any subscriber in such an areal desires to be informed of the correct time it is only necessary for him to call a directory number assigned to the time bureau Whereupon his line will be extended manually or automatically, dependent upon the character of the switching facilities of the oice in which his line terminates, either directly or through intermediate distribution centers to a trunk terminating in the time bureau. An operator at the time bureau upon receiving a signal indicating a request for the time of day will announce the correct time to the calling subscriber and to such other subscribers as may at the time have become connected to the time bureau. A system of this a character is disclosed in Patent No. 1,863,139

granted June 14, 1932 to R. F. Massonneau.

Since it is not economical to provide time bureaus in small exchange areas, it is the object of the present invention to supply time service to vsuch small exchange areas over toll trunks extending therefrom to the large exchange areas now equipped with time bureaus. Such an extension of time service over toll trunks necessitates the provision of'means for transmitting the time announcements and synchronizing'signals from the time bureau over the toll trunk to the toll point, the synchronizing signals being effective to insure that no connection from any calling subscribers line shall be cut through over the toll trunk to the time bureau except during a silent interval betwen time announcements whereby no subscriber will receive an incomplete announcement.

. In accordance with the present invention a toll trunk extending from the time bureau to the toll point is terminated at the toll point in the input side of a speech amplifier, the output side of which is branched to a plurality of local trunks. Access to the local trunk branches may be had in any desired manner dependent'upon the switching facilities of the toll point, for example, over manual connection jacks or over the banks of toll incoming or final selector switches. The output of the toll trunk amplifier is also connected through a lter circuit to the Winding of a tone responsive relay which may, for example, be re; sponsive to a 100,0 cycle tone current applied over the toll trunk at the time bureau during the silent relay and aout-through or announcement relay operable under the control of the tone relay when the local trunk is seized. `As soon as the local trunk is seized the pick-up relay of that trunk operates and locksduring the silent interval preceding 'the next time announcement since at that time the tone relay is operated in response to the 1000 cycle silent interval tone current. The tone relay at the beginning of the silent interval also causes the operation of a train of slow-to-operate" relayslandwith the last relay of the train operated the circuit of the cut-through relay is maintained open. At the end of the silent interval the tone relay releases in turn releasing the train of relays and thereupon the circuit of the cut-through relay is established. With both the pick-up and cut-through relays operated the local trunk is cut through to the toll trunk and the subscriber whose line has been connected to the local trunk hears the entire succeeding time announcement. At the end of the announcement the tone'relay againoperates in response Yto the silent interval tone current and after a predetermined interval the cut-through relay is released, but during the interval between the application of the silent interval tone current and the start of release of the cut-through relay, the subscriber hears alspurt of tone as an indication of the exact time previously announced.

For a more complete understanding of the invention reference may be had to the accompanying drawing.

The outgoing end of the toll trunk I extending from a toll point to the time bureau of a distance office is shown in the right portion of the drawing. This toll trunk would be connected through a distributing network to a time bureau such as is disclosed in the patent to Massonneau previously referred to. At the toll point the toll trunk I terminates in the primary winding of the repeating coil 2, the secondary winding of which is connected to the input side of an amplifier indicated by the box 3. The output side of the amplifier is branched to as many local trunks as are required to handle the time-of-day trafc, two of such local trunks 4 and 5 having been shown. The output side of theampliiier is also connected to a filter indicated by the box IS to the winding of the tone responsive relay 1. The lter 5 may be tuned, for example, to pass only 1000 cycle tone current transmitted from the time bureau during the "silent intervals between time'announcements.

Each local trunk such as 4 or 5 maybe accessible at the toll point from a toll operators position, or as disclosed, from a selector switch bank and is equipped with asleeve relay I0, a pick-up relay II, a cut-through or announcement relay I2, normally bridgedholding resistances I3 and I4, bridged retard coil I5 and serially connected @Ondensers I6 and I'I, and resistances I8, and I9.

' established at the Vselector switches'.

The tone responsive relay 'I operates at the beginning of each silent interval and remains operated until the termination of such interval and is effective upon operating to establish operating circuits for the pick-up relays of all calling local trunks and to control a delay circuit comprising slow-to-operate relays 8 and 9 for controlling the operating circuits for the cut-` through relays of all calling local trunks. The delay Vcircuit has been disclosed as comprising two successively operating sloW-to-operate relays 8 and 9, but it is to be understood that should a longer delay period be desired between the time of operation of tone relay 1 and the operation of relay 9, additional slow-to-operate relays could be interpolated between relays 8 and 9. v

When a subscriber in the toll area, desiring to receive an announcement of the time of day, initiates a call for such service, his line is connected over a switching train of any Well-known type to an idle one of the local trunks. It will be assumed that the trunk 4 is idle and that upon the seizure thereof the sleeve relay I Il ofthe trunk is operated. Relay I upon operating prepares operating circuits for the pick-up relay I I and for the cut-through relay I2 and prepares a locking circuit for the pick-up relay II. If the sleeve relay Ill operates during an announcement interval at which time relays 'I and 9 will not be operated, the circuit of cut-through relay I2 will be established from battery, over the upper contact of relay IIl to ground at the back contact Vof relay 9, but its operation will be ineffective to establish a listening connection over the local trunk 4 and t-he toll trunk I to the time bureau since with relay 1 unoperated the pick-up relay II cannot operate.

As soon thereafter as the announcement interval ceases, tone relay I will operate at the beginning of the following silent interval and with the sleeve relay I0 operated will establish an operating circuit from battery through the upper winding of cut-through relay I I, over the inner upper front contact of sleeve relay I0 to ground at the inner contact of tone relay 'I whereupon relay II will operate, lock through its lower winding and lower front contact to ground at the lower contact of sleeve relay I I] and at its transfer contacts remove the holding bridge through resistance I3 from across the local trunk and extend the trunk to the transfer contacts of the cut-through relay I2. Relay II will now remain operated until the connection with the incoming terminal of the local trunk is released. With the cut-through relay I2 operated the incoming end of the local trunk is now extended to the output side of the amplifier 3 through the condenser I6 and resistance I8 connected serially in the tip conductor and through the condenser II and resistance I9 connected serially in the ring conductor of the local trunk. At this time the retard coil I bridged across the talking conductors serves to hold the connection Since the subscribers line has been cut through to the time bureau during a silent interval the calling subscriber hears the silent interval tone.

When tone relay I operated at the beginning of the silent interval it also caused the operation of the delay circuit relays 8 and 9 and at the end of a predetermined interval relay 9 operated to open the operating circuit of cut-through relay I2 which upon releasing opens at its transfer contacts the talking conductors of the local trunk and bridges the holding resistance I4 across the trunk conductors to hold the connection to the local trunk. The spurt of silent interval tone which the subscriber hears is thus determined by the elapsed time between the operation of tone relay I and the operation of relay 9, but has no signicance at this time.

At the end of the silent interval the tone current is removed from the toll trunk at the time bureau and tone relay 'I thereupon releases followed immediately by the release of the relays 8 and 9 of the delay circuit. Thus, at the beginning of the following time announcement interval when relay 9 releases the operating circuit of cut-through relay I2 is established whereby the connection between the calling subscribers line and the time bureau is again established and the subscriber is enabled to hear the following complete time announcement. y 1

At the end of the time announcement, or at the beginning of the following silent interval, tone relay 'I again operates and causes the reoperation of relay 8 and 9 of the delay circuit, but during the interval between the beginning of the silent interval and the operation of relay 9, the subscriber hears a spurt of silent interval tone since until relay 9 operates the cut-through relay I2 remains operated. Te spurt of tone which the subscriber thus hears is effective at this time as a signal to the subscriber of the attainment of the exact time just previously announced. So long as the calling subscriber maintains the connection to the local trunk he will repeatedly heartime announcements followed by signaling tone at iifteen-second intervals. When, however, the calling subscriber no longer desiring tc hear time announcements, restores his receiver to the switchhook, the release of the connection to the local trunk is initiated andthe sleeve relay vII) is released in turn releasing the pick-up relay II and opening the operating circuits of the pick-up relay I I and the cut-through relay I2.

It will, of course, be obvious that several calling subscribers may concurrently receive timeof-day announcements over the several local trunk branches of the toll trunk, cross-talk or line disturbances between'the parallelly connected local trunk branches being prevented by the condensers IS and II and resistances I8 and I9 connected into the talking conductors of thesf local trunks.

What is claimed is:

l. In a telephone system having a time announcing bureau from which time-of-day an- ,Y

nouncements and a silent interval tone current are alternately transmitted, a toll oilice, an outgoing trunk local to said toll office, a toll trunk extending from said toll ofce to the time bureau, a relay associated with said toll trunk at the toll office and responsive to said silent interval tone current, means responsive to the operation of said relay during a silent interval and further means responsive to the release of said relay at the end of said silent interval to connect said local trunk to said toll trunk whereby the succeeding time announcement is transmitted over said local trunk. n

2. In a telephone system having a time announcing bureau from which time-of-day announcements and a silent interval tone current are alternately transmitted, a toll oce, an outgoing trunk local to said toll office, a toll trunk ex tending from said toll ofce tothe timeA bureau andterminating at saidtoll office in the input side of an amplier, a iilter circuit connected to the output side of said amplifier and tuned to be responsive to the frequency of said silent interval tone current, a relay associated with said lter circuit responsive to said tone current, means responsive to the operation of said relay during a silent interval and further means responsive to the release of said relay at the end of said silent interval to connect said local trunk to the output side of said amplier whereby the succeeding time announcement is transmitted over said local trunk.

3. In a telephone system having a time announcing bureau from which time-of-day announcements and a silent interval tone current are alternately transmitted, a toll oice, a plurality of outgoing trunks local to said toll oiice available from calling subscribers lines, a toll trunk extending from said toll office to the time bureau, a relay associated with said toll trunk at the toll ofce and responsive to said silent interval tone current, means associated with each of said local trunks responsive when said trunks are in a calling condition to the operation of said relay during a silent interval and further means associated with each of said local trunks responsive when said trunks are in a calling condition to the release of said relay at the end of said silent interval to connect said calling local trunks to said toll trunk whereby the calling subscribers may receive the succeeding time announcement.

4. In a telephone system having a time announcing bureau from which time-of-day announcements and a silent interval tone current are alternately transmitted, a toll oice, an outgoing trunk local to said toll office, a toll trunk extending from said toll oiiice to the time bureau, a relay associated with said toll trunk at the toll oiiice and responsive to said silent interval tone current, means associated with said local trunk responsive to the operation of said relay at the end of said silent interval to connect said local trunk to said toll trunk whereby the succeeding time announcement is transmitted over said local trunk, and delay means controlled by said relay for maintaining the connection between said local trunk and said toll trunk for a predetermined interval following the termination of the announcement interval whereby a short spurt of said silent interval tone current is transmitted over said local trunk.

5. In a telephone system having a time announcing bureau from which time-of-day announcements and a silent interval tone current are alternately transmitted, a toll oilice, a plurality of outgoing trunks local to said toll office available from calling subscribers lines, a toll trunk extending from said toll oftice to the time bureau, a relay associated with said toll trunk at the toll oice and responsive to said silent interval tone current, means associated with each of said local trunks responsive when said trunks are in a calling condition to the operation of said relay at the end of a silent interval to connect said trunks to said toll trunk whereby the calling of silent interval tone current is received by said calling subscribers.

6. In a telephone system having a time announcing bureau from which time-of-day announcements and a silent interval tone current are alternately transmitted, a toll oflice, an outgoing trunk local to said toll office, a toll trunk extending from said toll ollice to the time bureau, a relay associated with said toll trunk at the toll oice and responsive to said silent interval tone current, a pick-up relay associated with said local trunk operable in response to the operation of said tone responsive relay for partially connecting said local trunk to said toll trunk, a time delay circuit responsive to the operation of said tone responsive relay, and a cut-through relay associated with said local trunk and operable by said time delay circuit at the beginning of the succeeding announcement interval for completing the connection of said local trunk with said toli trunk. I

'7. In a telephone system having a time announcing bureau from which time-of-day announcements and a silent interval tone current are alternately transmitted, a toll oflice, an outgoing trunk local to said toll office, a toll trunk extending from said toll oliice to the time bureau, a relay associated with said toll trunk at the toll cnice and responsive to. said silent interval tone current, a pick-up relay associated with said local trunk operable in response to the operation of said tone responsive relay for partially connecting said local trunk to said toll trunk, a cut-through relay associated with said local trunk operable to complete a oconnection between said local trunk and said toll trunk, and a train of slow-to-operate relays controlled by said tone responsive relay for controlling the operation of said cut-through relay at the end of a silent interval and for maintaining said cut-through relay operated during the succeeding announcement interval and for a predetermined period following the termination of such announcement interval.

8. In a telephone system having a time announcing bureau from which time-of-day announcements and a silent interval tone current are alternately transmitted, a toll oice, an outgoing trunk local to said toll oice, a toll trunk extending from said toll office to the time bureau, a relay associated with said toll trunk at the toll office and responsive to said silent interval tone current, a sleeve relay for said local trunk operable upon the seizure of said trunk, a pick-up relay for said local trunk operable in response to the operation of said sleeve relay and the operation of said tone responsive relay for partially connecting said local trunk to said toll trunk, said pickup relay upon operating being maintained operated under the control of said sleeve relay, a cutthrough relay associated with said local trunk operable following the operation of said sleeve relay to complete a connection between said local trunk and said toll trunk, and a delay circuit controlled by said toll responsive relay for controlling the operation of said cut-through relay at the end of a silent interval and for maintaining said cut-through relay operated during the succeeding announcement interval and for a predetermined period following the termination of such announcement interval.

GEORGE F. DRUM.

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