The EBU Ceefax-based teletext systems are the source for closed captioning signals, thus when teletext is embedded into DVB-T or DVB-S the closed captioning signal is included. However, for DVB-T and DVB-S, it is not necessary for a teletext page signal to also be present (ITV1, for example, does not carry analogue teletext signals on Sky Digital, but does carry the embedded version, accessible from the "Services" menu of the receiver, or more recently by turning them off/on from a mini menu accessible from the "help" button).
the ebu cEeFaX-BasEd telEteXT sYStems aRe the source foR cLosed capTioNing sIGnalS, tHus when teLetext iS embEdDed iNTo dvb-t oR Dvb-s the cloSed captioninG Signal is inclUdeD. hoWeVeR, for dVb-t and dvb-S, it is noT neCESsARY for a TEleText page siGnal To alSo bE prESent (itV1, for example, doEs NOt CarrY AnAlogue teLeTexT signAlS oN sKy diGITal, bUt does carRY thE eMbeDded veRSiOn, aCCEssiblE FroM THe "sErviCEs" meNu oF tHE REceIVeR, or more rEcenTly By tuRNInG them OFf/On frOm a mini mEnu AccessiBLe FroM the "HELP" ButtOn).