GB1524812A - Data transmission line monitor - Google Patents

Abstract

1524812 Data transmission RANKS HOVIS McDOUGALL Ltd 29 Aug 1975 [4 June 1974] 24693/74 Heading H4P Apparatus nor monitoring signals in the form of groups each consisting of a preselected number of consecutive bytes each constituted by a preselected number of serially spaced bits, each group being identified by a synchronizing signal comprises a shift register 16 which receives said signals from an input amplifier stage 14; a logic circuit 18 responsive to the location of the synchronizing signal in the shift register to commence storage either of said group or a preselected subsequent group, and to operate a bit counter 42 to count the number of bits stored in the store 20, the logic circuit 18 being operable by the counter when the complete signal group has been stored to switch the apparatus to a display mode in which further signals are prevented from being stored; a display control in the form of a push-button (30) Fig. 3 (not shown) operable when the apparatus is in the display mode to pass each stored signal in sequence to the shift register 16, and a display unit 22 described in more detail with reference to Fig. 3 (not shown) adapted to provide a visual indication of both a signal in the register and the number of said signals in the group as calculated by the counter. The apparatus also includes a receiver 36 to retain said synchronizing signal and a comparator 34 to compare said signal with a signal in the shift register 20, the comparator transmitting a synchronizing pulse to the logic circuit 18 when the signals in the receiver and shift register are identical. The Specification describes how the apparatus may be used for monitoring signals which pass through teleprocessing transmission equipment using several lines for carrying out essential control function, whereby the condition of at least some of these lines can be indicated and faults can be detected and located.