Modem ringing suppression circuit

Abstract From the Canadian patent

An automatic telecommunication system includes a central location and at least one remote location where a data reporting system including a modem is situated. The central location establishes communications over the switched telephone network to the modem coupled to a telephone line at the remote location. At least one telephone handset is also connected to the telephone line at the remote location. Circuitry is provided for suppressing ringing of the telephone handset when the central location initiates a call to the modem at the remote location. The circuitry includes a microprocessor for controlling the modem to respond to incoming ringing signals on the telephone line only during a …