Wiki suggests Secam was teletext capable (or had been adapted or whatever, since it originally had 819 lines as opposed to the later European standard of 625 lines)
France and a few Francophone bordering countries ran 819 monochrome services, but these weren't SECAM services, they were B&W. You can't have B&W SECAM - as SECAM is specifically used to define the colour system only (The letters actually stand for "Séquentiel couleur à mémoire" or "Sequential colour with memory")
Whilst there may have been some 819 SECAM tests (just as the UK tested PAL, SECAM and NTSC 405) - it was never a formal system, and the days of 819 were (like 405 in the UK) numbered by the mid-60s. (Long before teletext)
France only had one 819 channel (what is now TF1) - the second channel (now France 2, previously Antenne 2 etc. ) which launched later was, like BBC Two in the UK, 625 B&W from launch, and then the 625 channel was upgraded to SECAM colour, whilst the 819 channel simulcast in 625 (and SECAM colour)
France's 625 SECAM services had Antiope (an incompatible French teletext standard) for quite a few years, until they switched to WST Teletext. (Incidentally France also modified their SECAM system to use a different chroma reference system - from 'bottles' in vertical blanking to horizontal idents, which freed up space in the vertical blanking period)
and anywhere that took the NTSC format was virtually doomed to failure. Argentina used 625 PAL as well but it appears to have been "butchered" for want of a better word for Closed Captioning support.
Argentina used 625 PAL but the PAL-N variant designed to fit into 6MHz channels, and as such used a 3.58ish rather than 4.43MHz subcarrier for colour (4.43MHz wouldn't have fitted in a 6MHz channel), and had reduced luminance bandwidth. Conventional 625 VBI teletext may not have worked that well there with the reduced bandwidth...
Brazil used 525 PAL M - which used a PAL colour encoding system at 525 lines with a 3.58ishMHz subcarrier - but would have had to have used a similar teletext system to NTSC M for bandwidth/line standard reasons I suspect.
Last edited by noggin on 7 February 2019 1:15am - 2 times in total