Arrangement for reducing character distortions in telegraph systems caused by the use of connecting lines of different lengths between subscriber and exchange
DE673200C
Exchange rate reporting system
DE566043C
Circuit arrangement for generating different frequency combinations by means of several AC sources
DE636580C
Rotary dial for automatic telephone systems
DE571904C
Circuit arrangement for testing and finding faults in automatic and semi-automatic telephone systems
DE580202C
Circuit arrangement for telephone systems with company lines
DE571975C
Circuit arrangement for automatic or semi-automatic telephone systems in which the voice dialer can be set with the aid of control circuits
DE553636C
Rotating indicator
DE582731C
Circuit arrangement for remote offices with several operator stations
DE610505C
Circuit arrangement for the communication between several independent telephones
DE578465C
Circuit arrangement for a selection level in an automatic or semi-automatic telephone system
DE532077C
Process for the production of spherical carbon cores, especially for use in microphones
DE574747C
Circuit arrangement for semi-automatic telephone systems
DE535550C
Arrangement for contact banks of voters in telephone systems
