Patent GB-1417599-A (GB)
Title: Hospital telecommunication system zig-zag folding apparatus
IPC: G08B3/10
Filed: 1973-07-06
Abstract: 1417599 Hospital intercommunication system ALOIS ZETTLER ELEKTROTECHNISCHE FABRIK GmbH 6 July 1973 [10 July 1972] 32264/73 Headings H4K and H4R [Also in Division G4] In a hospital intercommunication system for transmitting telecommunications signals between a central office and sub-units, e.g. beds, of a number of room units, each room unit has a characteristic high frequency which is a room unit signal and provides a carrier for the subunit addresses. At the central station a receiver is tunable to each of the room unit characteristic frequencies in succession in order to receive telecommunications signals from the room units. As described, the system may include facilities for use of the circuit for wired broadcasting of radio or television programmes, or closed circuit television, for the transmission of patient monitoring signals from the bed units to the central station, for location of a nurse, two-way conversation between a bed unit and a nurse at another room unit, via the central station, and for indicating the priority of the various calls incoming to the central station. In alternative forms the sub-unit addresses can be different low-frequency modulations of the room unit carrier or different digital codes modulating the room unit carrier. Central station. Figs. 6 and 7. A call from the central station is set up by operation of selector 131, Fig. 7, to enter the number of the bed required in store 132, the number being shown on indicator 139. A room counter 95 energizes each modulator 8 in turn, to select the different room units until the room count, as modified by a difference store which stores the difference in identity between the room count and the room identity matches the selected room number when the process is interrupted to allow communication to take place with the selected room unit. The input store energizes the appropriate one of the oscillators 55 to select the required bed and communication takes place. When a call is originated from a bed, or a door in a room unit, the call is received in the appropriate receiver 44, when the room counter enables the appropriate interrupt device 93 via switch 94, assuming that the priority of the call agrees with that registered with a priority test device 62 which determines the call of highest priority. The interrupt device, on stopping the switching of the switch unit 94, causes the number of the calling room to be shown on indicator 107. The particular bed originating the call is determined by the bed-receivers 51, or room receiver 53 according to the low-frequency modulation of the room unit carrier, and the number of the bed is displayed on the indicator 111. Should the patient require a nurse the operator at the central station presses key 113, which causes switches 97, 102, 106 to change over and, starting from the room number corresponding to the patient requiring a nurse, a search is made by search counter 115 alternately to room numbers above and below that number and the stations interrogated to determine if a "nurse present" key or detector has been operated so as to find the nearest nurse. When a nurse is found the room number is shown on indicator 119. Patient's bed unit, Fig. 4, comprises a call detector 16 which recognizes the appropriate carrier frequency and L.F. modulation corresponding to the bed and connects up the microphone and loud-speaker 14, 15 to allow intercommunication to take place. When a call is not being made the loud-speaker is connected to a wired broadcast receiver 21. A key 24 is operated to originate a call, by transmitting the bed unit's characteristic L.F. to the central station, the signal being modulated by pulses from unit 27 indicating the priority of the call. When the central station receives the call it transmits an acknowledgement which is received by 26 and switches off the oscillator 25. When the bed unit 5 receives both its characteristic frequency at receiver 16 and a measuring interrogation signal at receiver 30 a measure value from a patient monitoring apparatus 29 is transmitted back to the central station via transmitter 33. A room door unit, Fig. 5 (not shown) is similar to the bed unit except that it omits the wired broadcast receiver and the patient monitoring apparatus and includes a nurse present detector or switch to signal a nurse's presence in the room. Also described with respect to Fig. 12 (not shown), is a system in which the particular bed in a room and the type of call are indicated by a pulse code transmitted as modulation of the room unit characteristic frequency, and the central station uses only one high-frequency receiver which is tuned to the different room unit frequencies by changing the frequency of an oscillator supplying the receiver demodulator. In either system when a patient has called for a nurse and a nurse has been found a speech connection can be extended from the nurse to the patient via the central station by interconnecting the L.F. sides of the modems associated with the nurse and patient, Fig. 13 (not shown).