PURPOSE: To simplify the constitution of a button telephone set, by generating a dial pulse and a multi-frequency signal to a plurality of trunk lines according to individual dial numbers, through the control of the generation of dial pulses and a multi-frequency generating section with a common control section.

CONSTITUTION: A trunk line of a pulse dial system is provided with a pulse generating section PG and an original clock pulse CLK is generated in a control section CT using a microprocessor. The pulse CLK is frequency-divided at a frequency divider DV1 to form clocks in 1 and 2kHz of frequency, the clock CL is selected in response to the dial pulse speed transmitted at switching contacts t1∼t3, and applied to a counter CUT1 of the PG. When a dial pulse from a slave station is given to a control section CT, latch circuits LAT1 and LAT2 are operated according to a stobe signal LA, and the pulse is applied to the PG and a gate circuit G2 to control the generation of the dial pulse and the multi- frequency generating section, allowing to simplify the constitution of the button telephone set.