Abstract: A telephone switching office having essential service protection is disclosed. As each service request is received it is put in a common queue. Periodically, and regardless of the load, the common queue is examined for requests that have not been served with a given time interval. If these requests are from essential lines, they are put in a special queue. When a server, such as a digit receiver or processor is available the special queue is served prior to the common queue.

Abstract: For use in a multichannel time division multiplexed conference arrangement where the samples in one time frame of simultaneous speakers are summed for distribution to each of the conferees, the disclosed arrangement reduces the amount of speech that is often not heard (clipped) when a conferee first begins to speak. The arrangement features a delay unit which stores all the speech samples from one time frame for a period of time greater than the processing time required to detect and determine whether to include speech samples from a new speaker in the distributed sample. By first storing the samples from one time frame and then summing the stored samples, any samples from a new speaker may be included in the resulting output sample to reduce speech clipping.

Abstract: A telephone network having an audio/data conference arrangement wherein a billing record is kept for each audio and data conference leg and each conference bridge. Suitable billing allowances are computed if a conference leg is used to reestablish another leg that had disconnected. Also, billing for all audio conference legs is interrupted while an operator is connected to the conference.

Abstract: A communications network having a multiport data conference system is disclosed. The data conference system includes a multilevel processor arrangement with the lower level port processors communicating directly with data terminals and higher level processors controlling conference configuration. Data to be conferenced is put in a buffer memory which is shared by all levels of processors. The ports can be configured to be compatible with different type terminals that operate at different data speeds.

Abstract: A network services complex having an audio conference bridge, a data conference bridge, a tone receiver and a data store announcement system is disclosed. The complex is connected to a telephone network via a host toll switching center. Customers dialing over the network using a keyset can selectively establish audio-only, data-only and combined audio/data conferences. Announcements from the data store prompt the customer in the use of the arrangement and request the user to reenter information when the customer makes an error. Should the customer make too many errors, an operator is summoned.

Abstract: A processor controlled conference arrangement is connected to a host switching system. The availability of conference resources (e.g., ports, registers, etc.) and processor real time capacity is measured before a call is forwarded to the conference arrangement.

Abstract: A telephone switching office is disclosed having a public announcement system wherein new announcements can be recorded or priorly recorded announcements can be updated via the telephone network. The producer dials a number associated with the announcement to be updated and transmits the update announcement to the office. In order to verify the announcement with an authorized party, the switching office calls the producer at a preassigned station and plays back the update announcement. If the producer disconnects before the playback is completed, the playback announcement is aborted; otherwise, the new version is made active and the former announcement is removed from service.

Abstract: A service-observing arrangement is disclosed for automatically detecting and classifying interrupted tone signals (such as audible ringing, busy, reorder, etc.) which appear on telephone lines. These signals have a certain "pitch rate" discernible by the listener and caused by the combining of a plurality of separate tone signals.The line is scanned and the signals on the line are first passed through a filter to filter out all frequencies within the "pitch rate" spectrum and are not fundamental components of the interrupted signal. The remaining signal is then modulated to produce a significant energy component at the "pitch rate" only if legitimate signals are present. The ratio of pitch rate energy to total energy is then compared to threshold values and its cadence and power consistency are checked to identify the signal.

Abstract: An arrangement for keying plug-in circuit boards and their receptacles so that a user is alerted visually and audibly if an attempt is made to insert a board into an improper receptacle. Contacts on the board are arranged in coded locations along the edges of the board which slide into the guide rails of the receptacles. Contact assemblies are mounted on the guide rails in a similar coded arrangement. The contacts and contact assemblies are positioned in such a manner that at least one board contact will electrically engage a receptacle contact assembly and energize an alarm before the board can be fully inserted into an improper receptacle.

Abstract: An electrical jack is disclosed having an elongated nonconductive housing with a cylindrical opening for receiving a plug having tip, ring, and sleeve members. Corresponding tip, ring, and sleeve spring assemblies are positioned in the housing generally transverse to the cylindrical opening for engagement with the plug members and each assembly has a pair of break contacts which are opened to interrupt circuitry connected thereto, when the plug is fully inserted into the jack opening. The ring spring assembly is further arranged to engage the tip of the plug when the plug is partially inserted. The ring spring assembly positions the plug so that the tip and ring of the plug engage the ring and sleeve spring assemblies of the jack without opening the break contacts. Partial insertion of the plug permits bridging onto the circuit connected to the jack without interrupting the continuity of the circuitry connected through the break contacts.

Abstract: A telephone network having a public announcement system is disclosed. Announcements are divided into message segments each of which is stored in a sector of a disc memory. When an announcement is activated, the message segments are loaded into a corresponding number of buffers for transmittal to calling customers. Each buffer will transmit the entire message, but in real time the buffers contain different message segments. Upon request for an announcement, the buffer containing the beginning message segment is selected to minimize holding time and customer waiting.

Abstract: A buffer circuit is disclosed as part of a centralized subsystem in a telephone switching system. The subsystem performs all functions heretofore performed by individual originating registers and communicates with office pretranslators for effecting digit pretranslation. The buffer circuit interfaces a computer of the subsystem with a conventional pretranslator connector for obtaining access to the office pretranslators preferentially over originating registers which are competing for the pretranslators. In response to a single call, the buffer applies a bid for service to each of a plurality of pretranslator connector subgroups in contrast with a bid to a single subgroup from each originating register. In the event the computer receives overlapping calls, the buffer circuit holds the multiple bids for service to preserve their priority status in the queues of the connector subgroups.