Cable television stations can generally operate at a higher signal-to-noise ratio and can use either the 16VSB as defined in ATSC or the 256-QAM defined in SCTE, to achieve a throughput of 38.78 Mbit/s, using the same 6 MHz channel.
Currently, the Federal Communications Commission requires cable operators in the United States to carry the analog or digital transmission of a terrestrial broadcaster (but not both), when so requested by the broadcaster (the "must-carry rule").