Details of selecting apparatus or arrangements for establishing connections among stations for the purpose of transferring information via these connections

HELECTRICITY H04Electric communication H04QSELECTING

H04Q1/00Details of selecting apparatus or arrangements for establishing connections among stations for the purpose of transferring information via these connections

H04Q1/02Constructional details H04Q1/021using pivoting mechanisms for accessing the interior of the apparatus H04Q1/023using sliding mechanisms for accessing the interior of the apparatus H04Q1/025Cabinets H04Q1/026characterized by door details H04Q1/028Subscriber network interface devices H04Q1/03Power distribution arrangements H04Q1/032power failure protection H04Q1/035Cooling of active equipments H04Q1/04Frames or mounting racks for selector switches Accessories therefor H04Q1/06Cable ducts or mountings specially adapted for exchange installations H04Q1/062vertical management arrangements H04Q1/064horizontal management arrangements H04Q1/066arranged on the front side H04Q1/068arranged on the rear side H04Q1/08Frames or mounting racks for relays Accessories therefor H04Q1/09Frames or mounting racks not otherwise provided for H04Q1/10Exchange station construction H04Q1/11Protection against environment H04Q1/112mechanical protection H04Q1/114flooding protection H04Q1/116lightning or EMI protection H04Q1/118heat or sun protection H04Q1/12Arrangements of multiple bars with or without pivotable frames H04Q1/13Patch panels for monitoring, interconnecting or testing circuits H04Q1/131being pivotable H04Q1/133being slidable H04Q1/135characterized by patch cord details H04Q1/136having patch field management or physical layer management arrangements H04Q1/138using RFID H04Q1/14Distribution frames H04Q1/141Details of connexions between cable and distribution frame H04Q1/142Terminal blocks for distribution frames H04Q1/143with contacts on circular surface H04Q1/144Plugs used in distribution frames H04Q1/145with switches arranged in a matrix configuration H04Q1/146with line protection means H04Q1/147using robots for distributing H04Q1/148Identification strips for distribution frames H04Q1/149Wireguides in connector blocks H04Q1/15Backplane arrangements H04Q1/155characterised by connection features H04Q1/16Wiring arrangements for selector switches or relays in frames H04Q1/18Electrical details H04Q1/20Testing circuits or apparatus Circuits or apparatus for detecting, indicating, or signalling faults or troubles H04Q1/22Automatic arrangements H04Q1/24for connection devices H04Q1/245in time-division multiplex systems H04Q1/26for signalling trouble in unoccupied sub-exchanges H04Q1/28Current-supply circuits or arrangements for selection equipment at exchanges H04Q1/30Signalling arrangements Manipulation of signalling currents H04Q1/32using trains of dc pulses H04Q1/34Impulse regenerators with mechanical or other non-electrical marking arrangements H04Q1/36Pulse-correcting arrangements H04Q1/38using combinations of direct currents of different amplitudes or polarities over line conductors or combination of line conductors H04Q1/39using coded pulse groups H04Q1/40whereby duration of pulse or interval between two pulses is variable H04Q1/42involving the position of a pulse in a cycle H04Q1/44using alternate current H04Q1/442with out-of-voice band signalling frequencies H04Q1/4423using one signalling frequency H04Q1/4426using two or more signalling frequencies, transmitted in succession or simultaneously H04Q1/444with voice-band signalling frequencies H04Q1/446using one signalling frequency H04Q1/4465the same frequency being used for all signalling information H04Q1/448with conversion of a single frequency signal into a digital signal H04Q1/4485which is transmitted in digital form H04Q1/45using multi-frequency signalling H04Q1/453in which m-out-of-n signalling frequencies are transmitted H04Q1/4535with an additional signal transmitted for voice protection H04Q1/457with conversion of multifrequency signals into digital signals H04Q1/4575which are transmitted in digital form H04Q1/46comprising means for distinguishing between a signalling current of predetermined frequency and a complex current containing that frequency H04Q1/48Induced-current signalling arrangements H04Q1/50Conversion between different kinds of signals H04Q1/54Amplifier switched-on automatically in dependence on automatically-selected lines H04Q1/56Balancing circuitry switched-on automatically in dependence on automatically-selected lines