47 CFR § 80.351
Scope
February 16, 2021
The following sections describe the carrier frequencies and general uses of radiotelegraphy and data transmission with respect to the following:
(a) Distress, urgency, safety, call and reply.
(b) Working.
(c) Digital selective calling (DSC).
(d) Narrow-band direct-printing (NB-DP).
(e) Facsimile.
(f) VHF-FM digital small message services (VDSMS).
[81 FR 90747, Dec. 15, 2016]