| 摘要 |
<p>A switching and distributing device with a central unit and a multiplicity of connected subscribers is proposed. All the terminals of a subscriber are interconnected by two two-wire lines which are independent of one another. One two-wire line carries the information coming from the central unit, the other the information going to the central unit. Only one of the connected terminals (main unit H) transmits back to the central unit Z. The remaining connected terminals are secondary units N. Information from a secondary unit N to the central unit Z passes via the main unit H. One wire of the two two-wire lines is used in each case to link the main unit H with the secondary units N. <IMAGE></p> |
