47 CFR § 74.783 - Station identification.
(a) Each low power TV station as defined by § 74.701(f) must transmit its station identification using one of the following methods:
(1) When originating programming, as defined by § 74.701(h), a low power TV station may use the station identification procedures given in § 73.1201 of this chapter on its primary stream. Other streams may use the method in paragraph (a)(2) of this section. The identification procedures given in the remainder of this paragraph are to be used at any time the station is not originating programming; or
(2) By transmitting the call sign in the short channel name field of the Program and System and Information Protocol (PSIP) (or its ATSC 3.0 equivalent) for at least one stream on the station. If the station is assigned an alphanumeric call sign consistent with § 74.791(d) and its call sign has more than 7 characters, it may drop the “-D” from the end of the call sign when identifying with this method; or
(3) By arranging for the primary station, whose signal is being rebroadcast, to identify the low power TV station by transmitting an easily readable visual presentation or a clearly understandable aural presentation of the low power TV station's call letters and location. Two such identifications shall be made between 7 a.m. and 9 a.m. and 3 p.m. and 5 p.m. each broadcast day at approximately one hour intervals during each time period. Television stations which do not begin their broadcast day before 9 a.m. shall make these identifications in the hours closest to these time periods at the specified intervals.
(b) Licensees of television translator stations may arrange for identification via the method in paragraph (a)(3) of this section. Licensees of television translators who make such arrangements for station identification to be made by the television station whose signals are being rebroadcast by the translator, must secure agreement with this television station licensee to keep in its file, and available to FCC personnel, the translator's call letters and location, giving the name, address, and telephone number of the licensee or his service representative to be contacted in the event of malfunction of the translator. It shall be the responsibility of the translator licensee to furnish current information to the television station licensee for this purpose.
(c) Transport Stream ID (TSID) values are identification numbers assigned to stations by the FCC and stored in the Commission's online database. Two sequential values are assigned to each station.
(1) All low power TV stations originating programming shall transmit their assigned odd-numbered TSID, if one has been assigned. All TV translator stations, and low power TV stations not originating programming, shall pass through the assigned TSID of the originating station, unless the translator or low power TV station is modifying the signal of one or more originating stations in such a way that it is not clear which originating station's TSID should be used. In that case, the station shall transmit its assigned odd-numbered TSID if one has been assigned.
(2) In ATSC 3.0, a similar value is used called a Bit Stream ID (BSID). LPTV stations operating in ATSC 3.0 mode shall utilize their assigned even-numbered TSID as their BSID, and LPTV/translator stations shall transmit the BSID as otherwise required of the TSID in paragraph (d)(1) of this section.