Surely the legend is wrong? It claims that the “go” and “return” lines of a given signal pair are in opposite wire pairs, which is definitely incorrect. Additionally, DM cable is not just two twisted pairs next to each other. DM cable means that twisted pairs are taken and twisted into pairs of pairs, then two of those twisted together (4 pairs), then a pair of those (8 pairs) etc. But a pair always remains a pair, you don’t send half of a signal down one pair and the other half of a signal down another pair. See https://books.google.com/books/about/Radio_and_Line_Transmission.html?id=0hESBQAAQBAJ and figure 1 and description of https://worldwide.espacenet.com/patent/search/family/032542359/publication/GB190312526A?q=pn%3DGB190312526 — tooki (talk) 12:02, 13 April 2020 (UTC)
- That's not what the legend means. GO and RETURN are the pairs. Legs A and B are the conductors of a pair. GO and RETURN was common terminology on telephone trunk lines for the transmitting and receiving pair respectively. SpinningSpark 12:24, 13 April 2020 (UTC)
- Hi! Thanks for responding so quickly! I’ve since found the existing discussion on the matter on the balanced line page. I’m making a proposal as to a clearer wording there, which would make the legend unambiguous.
- The issue of the two pairs being depicted as not twisted together remains, though, as the pairing-of-pairs is the defining characteristic of DM cable, as opposed to ordinary twisted-pair that just has the pairs bundled alongside each other. See especially the image in the patent linked above. (Or, if you can read German, the explanation at https://de.wikipedia.org/wiki/Viererverseilung ).
- Best regards! — tooki (talk) 12:41, 13 April 2020 (UTC)
