A telephone keypad is a standard 3x4 grid of buttons found on traditional telephones, mobile phone touchscreens, and intercom systems, featuring numbers 1 through 9, zero (0), the asterisk (*), and the pound/hash sign (#). Developed for Dual-Tone Multi-Frequency (DTMF) signaling, each button press generates a unique pair of audio frequencies that transmit call routing signals to the telephone network. On modern smartphones, this grid is represented digitally inside the phone application dialer tab. You can verify this layout by checking any standard phone dialing interface.
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