Patents Assigned to Deutsche Telephonwerke und Kabelindustrie Aktiengesellschaft
  • Hybrid circuit
    Patent number: 4301336
    Abstract: Hybrid circuit for transition between two-wire and four-wire lines includes first and second operational amplifiers each having an inverted and non-inverted input and output, a voltage divider connected to each of the inverted inputs, a bidirectional terminal connecting the two-wire side to the non-inverted input of the first amplifier and a transmit terminal connecting the four-wire side to the non-inverted input of the second amplifier, to feed audio voltage to the non-inverted inputs, the voltage dividers having equal resistances, a receive terminal for connecting the four-wire side to the output of the first amplifier, matching impedances connected to the non-inverted input of the second amplifier and the output of the first amplifier, the matching impedances and an impedance balancing the impedance of the two-wire side compared to input impedances to the hybrid circuit being such that, for an incoming transmission, half of the output voltage of the second amplifier is at the non-inverted input of the fir
    Type: Grant
    Filed: April 16, 1979
    Date of Patent: November 17, 1981
    Assignee: Deutsche Telephonwerke und Kabelindustrie Aktiengesellschaft
    Inventor: Frank Muting
  • Telephone handset
    Patent number: D242928
    Type: Grant
    Filed: February 7, 1975
    Date of Patent: January 4, 1977
    Assignee: Deutsche Telephonwerke und Kabelindustrie Aktiengesellschaft
    Inventors: Karl Buchin, Werner Grosse, Wolfgang Klein, Alfred Wloch
  • Telephone instrument
    Patent number: D243961
    Type: Grant
    Filed: February 7, 1975
    Date of Patent: April 5, 1977
    Assignee: Deutsche Telephonwerke und Kabelindustrie Aktiengesellschaft
    Inventors: Karl Buchin, Werner Grosse, Wolfgang Klein, Alfred Wloch, Manfred Seide
  • Desk telephone station with built-in freespeaking device and an additional casing for a sound transmitter and/or receiver
    Patent number: D244468
    Type: Grant
    Filed: April 19, 1976
    Date of Patent: May 24, 1977
    Assignee: Deutsche Telephonwerke und Kabelindustrie Aktiengesellschaft
    Inventor: Karl Buchin
  • Desk telephone station with built-in freespeaking device
    Patent number: D244469
    Type: Grant
    Filed: April 19, 1976
    Date of Patent: May 24, 1977
    Assignee: Deutsche Telephonwerke und Kabelindustrie Aktiengesellschaft
    Inventor: Karl Buchin
  • Telephone communication terminal set
    Patent number: D299343
    Type: Grant
    Filed: May 27, 1987
    Date of Patent: January 10, 1989
    Assignee: Deutsche Telephonwerke und Kabelindustrie Aktiengesellschaft
    Inventor: Georg Friedrich