US 4,069,402 AGranted

Remote-testing arrangement for PCM transmission system

AssigneeSociete Italiana Telecomunicazioni Siemens S.p.A.

InventorsPietro Mantovani, Silvio Roldi

Life of this patent

Estimating the term…

Loading patent…

Abstract

Two sets of line terminals in a pair of PCM head stations are interconnected by a set of transmission channels via a number of cascaded relay stations each including a line repeater for each channel. A service link extends from an address generator in one head station to a monitoring unit in each relay station, the monitoring unit including a regenerating circuit for throughgoing address codes and further including a discriminating network which, upon detecting an address code identifying that relay station, sends a sinusoidal priming signal to all the associated repeaters. A predetermined PCM test code, e.g. one containing a certain number of consecutive zeroes, is simultaneously transmitted from the same head station over the channel containing a selected repeater to be checked which, upon coincidence of the test code with the priming signal from the associated monitoring unit, closes a loop for feeding back the test code to the originating line terminal.

Claims10

Dependent claims

In a pulse-code-telecommunication system including a pair of head stations interconnected by a set of parallel two-way transmission channels, a set of line terminals at each head station respectively connected to said transmission channels, and a plurality of cascaded relay stations between said head stations, each relay station encompassing a set of line repeaters respectively inserted in said channels, the line terminals of one head station being adapted to transmit over the associated channel a test code for checking a selected line repeater inserted therein, each line repeater being provided with loop-closing means for retransmitting said test code to the originating line terminal,

the combination therewith of:
a service link extending from said one head station to all said relay stations;
a monitoring unit at each relay station connected to said service link;
signal-generating means at said one head station connected to said service link for transmitting thereover an address code identifying the monitoring unit of a relay station containing the selected line repeater;
discriminating means at each monitoring unit responsive to the corresponding address code for delivering a priming signal to all the line repeaters of the relay station so addressed;
receiving means at each line repeater responsive to said test code for emitting a recognition signal;
and
coincidence means at each line repeater connected to said receiving means and to said monitoring unit for operating said loop-closing means under the joint control of said priming and recognition signals.

5 more elements

Dependencies are inferred from the claim text.