PURPOSE: To provide a memory card for an extension telephone set capable of utilizing personal abbreviated numbers or the like in the various kinds of locations.

CONSTITUTION: A key part 33 capable of selecting the abbreviated numbers or the like and a speaker 35 for transmitting PB signal sound or the like are incorporated in the memory card 3. Then, by adhering the speaker 35 to the transmitter of a public telephone set, operating the key part 33 and inputting the abbreviated number, the PB signal sound is outputted from the speaker 35. Thus, even at an outside, when the line is a PB line, a call can be originated using the abbreviated number similarly to the extension telephone set normally used.