Telephone number selection mode switching system - detects acceptability of selection mode by central exchange to transmit full number or switch to alternate selection mode

摘要

The mode switching system, for automised telephone switching determines whether or not the number selection mode is acceptable by the central exchange after transmission of the first number of each telephone number, to allow transmission of the following number, or switching to the alternate selection mode. Pref. the acceptability of the transmitted numbers is indicated by use of an audible tone, with subsequent switching between a pulse selection mode and a multi-frequency code selection mode. USE - For automatic switching to appropriate number selection mode.