GB1066621A - Improvements in or relating to communication systems - Google Patents

Abstract

1,066,621. Repeater systems. SIEMENS A.G. Sept. 22, 1964 [Sept. 23, 1963], No. 38521/64. Heading H4R. A four-wire circuit between a pair of attended stations, e.g. HV1 and HV2, is provided with a number of repeaters arranged in two groups; a first group, e.g. Via, V2a ... Vna, associated with and powered by one attended station i.e. HV1 and the second group, e.g. V1b, V2b . . . Vnb, associated with and powered by a second attended station i.e. HV2. Each repeater includes a band-pass filter, e.g. F1, F2 ... Fn, connecting the go and return paths on the side of the repeater distant from the associated attended station so that test signals of the appropriate frequency transmitted from the attended signal will be returned via the band-pass filter and so allow transmission monitoring of the intermediate repeaters. The filters F1, F2 &c. may be of different frequency pass band so that a test signal of appropriate frequency will test specific repeaters or the filters may be similar and a pulse-type test signal may be applied, the response of different repeaters being distinguished by reference to the different transit times through the different repeaters. The junction between repeaters Vna and Vnb is provided, e.g., with a transformer to isolate the two groups of repeaters as far as the power supplies are concerned, and also with a filter to isolate a test signal applied to one group from the repeaters of the second group. The repeaters may be of standard construction utilizing plugin band-pass filters; and the separating filter and power supply isolator may be contained in a separate plug-in unit.