Telomeric DNA-binding protein, which binds to two or more single-stranded G-rich repeat sequences (G-strand), with high specificity to the 5'-TTAGGC-3' sequence (PubMed:18329362, PubMed:23390606). In addition, repeat sequence binding requires a 3' single-stranded telomeric overhang (PubMed:18329362). Acts redundantly with pot-1 to negatively regulate telomerase-mediated telomere extension (PubMed:18329362, PubMed:23390606, PubMed:24297748). Also regulates telomere length by the telomerase-independent telomere maintenance pathway called ALT (alternative lengthening of telomeres) (PubMed:23390606, PubMed:22547822, PubMed:24297748). Does not appear to have a role in anchoring telomeres to the nuclear envelope (PubMed:24297748). Belongs to the telombin family.