Telephone subscriber's appts. with buffer register - stores earth key function by applying signal to buffer register before leading digit

摘要

The telephone instrument has a buffer register to temporarily store subscriber numbers. A programmable pause can be inserted between two consecutive digits when dialling pulses are formed. An earth key is also provided. The earth keying function is stored before the leading digit of a call number by applying a signal to the buffer register. If this signal does not appear before the leading digit of the stored number, it generates the pause during the dialling pulses transmission.