> 988
Collection of 3 Digit Phone Numbers:
https://en.wikipedia.org/wiki/Category:Three-digit_telephone_numbers
Dual-tone multi-frequency signaling (DTMF)
DTMF is a telecommunication signaling system using the voice-frequency band over telephone lines between telephone equipment and other communications devices and switching centers.
DTMF was first developed in the Bell System in the United States, and became known under the trademark Touch-Tone for use in push-button telephones supplied to telephone customers, starting in 1963. DTMF is standardized as ITU-T Recommendation Q.23. It is also known in the UK as MF4.
DTMF keypad frequencies are a combination of two sounds, for example:
9 = 1477 Hz and 852 Hz
8 = 1336 Hz and 852 Hz
In addition to 0-9 and & and #, DTMF also supports A-D
D = 1633 Hz and 941 Hz
https://en.wikipedia.org/wiki/Dual-tone_multi-frequency_signaling