DtmfKey
DtmfKey.freqs()
DtmfKey.from_char()
DtmfKey.to_char()
DtmfTone
DtmfTone.high_hz
DtmfTone.key
DtmfTone.low_hz
DtmfTable
DtmfTable.all_keys()
DtmfTable.all_keys_matrix()
DtmfTable.all_tones()
DtmfTable.all_tones_matrix()
DtmfTable.from_pair_exact()
DtmfTable.from_pair_normalised()
DtmfTable.from_pair_tol_f64()
DtmfTable.from_pair_tol_u32()
DtmfTable.lookup_key()
DtmfTable.nearest_f64()
DtmfTable.nearest_u32()
LOWS
HIGHS
dtmf_table