Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M3/00—Automatic or semi-automatic exchanges
  • H04M3/42—Systems providing special services or facilities to subscribers
  • H04M3/42314—Systems providing special services or facilities to subscribers in private branch exchanges
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M9/00—Arrangements for interconnection not involving centralised switching
  • H04M9/001—Two-way communication systems between a limited number of parties
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M19/00—Current supply arrangements for telephone systems
  • H04M19/02—Current supply arrangements for telephone systems providing ringing current or supervisory tones, e.g. dialling tone or busy tone

Definitions

• the invention relates to an intercom system according to the preamble of claim 1.
• Intercom systems of various types are known (Spitta: "Electrical installation technology", second part, Siemens Aktiengesellschaft, Berlin-Munich, 1971, pages 1044 ff.) This is how a distinction is made between door intercom systems, house intercom systems and speakerphone systems.
• intercoms serve exclusively for internal speech communication, work without a switching device and in which the intercom stations are directly connected to one another via lines.
• a speech system is already known from SEL messages 16 vol. (1968), number 2, pages 81-85, in which the establishment of a connection is made audible in the speakers of the microphone units by a call signal.
• intercoms can also be operated in connection with remote intercom systems. From a Siemens product font: "System HICOM 600", order no. A19100-K3161-G430-01, a telephone private branch exchange with an interface is known to which several door hands-free systems with door opener function can be connected.
• the door hands-free system can be queried from any voice terminal by dialing a code and the door can then be opened by dialing (page 23 of the product brochure).
• the known telephone extension system also realizes the "hands-free" feature, which enables a subscriber with a hands-free device to make calls via an integrated microphone and an integrated loudspeaker without using the handset. During hands-free operation, you can switch to handset operation (and vice versa) (pages 39 and 44 of the product specification).
• High quality intercom systems are characterized by their extensive freedom from noise.
• intercom connection The establishment of an intercom connection, its existence and termination at the intercom to which the intercom connection has been set up, goes unnoticed unless acoustic signals are input into the transmitting device of the intercom initiating the intercom connection (speech, noise , Etc.).
• Intercom connections for example unintentionally and unnoticed, can thus continue to exist without information being transmitted in both directions between the two intercom stations.
• the unnecessary continuation of an intercom connection requires electrical energy and prevents further intercom connections with possibly further intercoms of the intercom.
• the invention is therefore based on the problem of designing an intercom system of the type mentioned at the beginning in such a way that the existence of an intercom connection is clearly recognizable even for largely noise-free systems for subscribers of the connection.
• intercom system according to the invention thus also meets data protection requirements: The possible. Misuse of unnoticed eavesdropping is ruled out.
• a sound signal generator is also used for the reception part of the microphone unit establishing the intercom connection supplies sound signals. The operator of the intercom initiating the intercom connection is thus made aware of the continued existence of the intercom connection.
• At least one of the microphone units is formed by a subscriber terminal of a telephone extension unit that realizes the two-way connections.
• this embodiment can be implemented in a simple manner by changing the control program, in which case existing hardware components are used.
• FIG. 1 A preferred embodiment of the intercom system according to the invention is shown in the FIGURE.
• This consists of a private branch exchange PBX with two microphone units Tl, T2.
• Each call station comprises a transmitting part and a receiving part.
• the intercom Tl which triggers the intercom connection in a manner known per se, this is the transmitting part S1 and the receiving part
• the transmitting part S1, S2 is each formed by a microphone and the receiving part E1, E2 is each formed by a loudspeaker or the earpiece, which is integrated in the handset of a telephone device.
• a tone signal generator P is arranged in the private branch exchange PBX. This is particularly due to an existing in the private branch exchange Tone generator formed.
• a control program is assigned to a control of the private branch exchange PBX, not shown in the FIGURE, which, in a manner known per se, realizes the “two-way communication” (direct answer / direct answer) feature.
• Subscriber stations with an integrated microphone and an integrated loudspeaker are provided in the introduction to the description.
• An intercom connection can be established from a first to a second subscriber station.
• the operator of the second subscriber station can automatically, i.e. without switching action, answer the switched-on microphone or lift the handset and answer it.
• control program is designed in such a way that the sound signal generator P feeds sound signals to the receiving part E2 of the station T2 to which the intercom connection has been set up.
• the switching command of the intercom Tl which triggers the intercom connection switches the sound signal generator on to the receiving part E2 of the intercom.
• the sound signal generator can be connected to the receiving unit E1 of the intercom Tl which triggers the intercom connection.
• a first sound signal is fed to the receiving part E2 and, if appropriate, to the receiving part E1 at the start of the intercom connection; then further sound signals cyclically E2 and possibly El are fed.
• a 425 Hz tone with a level of -3dBm0 is used as the tone signal.
• a tone duration of 100 ms and a pause duration of 20 s can be determined.
• the tone signal generator P is connected to a speech level detector D, which in turn can be connected to the receiving part El of the intercom Tl which triggers the intercom connection.
• the known voice level detector D recognizes the speech or noise level of the receiving part E1 and generates a signal upon detection of a speech or noise level on the output side which, in conjunction with a timing element not shown in the FIGURE, temporarily deactivates the audio signal generator for a predefinable time.
• the sound signal generator P triggered by the signal emitted by the detector D, is separated from the receiving part E1 or E2 as part of the existing connection.
• the intercoms T1, T2 can also be equipped with an optical display device, which alternatively or cumulatively displays an intercom connection to the audio signals supplied to the intercoms T1, T2.
• This function is also implemented in the telephone private branch exchange mentioned in the introduction to the description by a corresponding change in the control program, again using existing hardware components.

Landscapes

• Engineering & Computer Science (AREA)
• Signal Processing (AREA)
• Interconnected Communication Systems, Intercoms, And Interphones (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6447439

Family Applications (1)

Country Status (2)

Citations (2)

• 1991
  • 1991-12-18 DE DE19914141887 patent/DE4141887C1/de not_active Expired - Lifetime
• 1992
  • 1992-12-10 WO PCT/DE1992/001032 patent/WO1993012621A1/de unknown

Patent Citations (2)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events