Switching device for automatic allocation of telephone line between several users - has selector connected to network line and to payment device associated with each user terminal to detect valid payment by phone card

摘要

The selector (1) has a switching matrix (4) to make a connection between the network line (LT) and the user telephone lines (L1-Ln) which call or are called. An incoming call direct selector (5) controls the matrix for incoming calls to all lines, while an outgoing call direct selector (8) does so for outgoing calls on two-way lines and can detect the unhooking of a telephone. A phone card reader and associated managing microprocessor detects valid payment, and the line is connected if this condition is satisfied and the telephone is unhooked. A microcontroller prevents the action of the two direct selectors while a user is connected to the network. A voice synthesiser (7) may ask the incoming caller for additional digits to identify a particular terminal. USE/ADVANTAGE -E.g. in blocks of flats, public telephones. Increased line traffic without increasing number of lines. Allows separate charging of users.