35b was expected for 2016 but wasn't ready, the Germans say. The improved 35b vectored VDSL uses more spectrum to get speeds of 200 megabits or so up to 300-400 meters. That's not close to the 500-800 megabits G.fast can do over short loops but in some cases saves the telco a lot of money. G.fast can't share the wire binder with the old 17 MHz VDSL but 35b can. Deutsche Telekom has millions of the 17 MHz modems they don't want to replace so chose 35b. Unfortunately, the new systems aren't delivering what DT requires.
Philipp Blank of DT tells Ashun Sawall of Golem.de, ""The technology has to be tested and then rolled out. That will not happen overnight. Part of the problem is the Super-vectoring technology itself. The linecards need to be installed nationwide in the multifunctional housings. We must adapt the product portfolio and the product variants in the IT systems. Finally, we do not have any end devices for customers." Tom Stanton of Adtran a major American supplier who also sells to Telekom, does not expect 35b in volume before 2018.
However, at least three vendors claim they are ready to ship the "end devices." The Italians have already installed more than 10,000 ports and are widely advertising the "200 megabits." These are all reputable outfits, but none of them will explain the discrepancy.
If they are all telling the truth - which I think they are - I can only guess what's going on. I assumed that the Italians selling 200 megabits were using 35b, the only way to get those speeds I know. But when I spoke to them, they told me, "70% of those customers are getting 130 megabits or more downstream." The Italians have very short loops, averaging ~ 250 meters. 35b is designed to deliver about twice the 130 meg they are reporting. Adtran's lab tests confirm the expected results, See my article, below.
The 130 megabit speeds would be consistent with using 35b gear without the vectoring noise cancellation that is designed into the standard. That would typically cut the speeds in half. The calculations to vector dozens of lines are intense, so Huawei and Adtran have moved the vectoring off the line card to an external box. The equivalent vectoring box for G.fast is late. It was promised to customers for mod-2016 but none have been seen in the field. There's a rumor that Britosh Telecom has some external vectoring boxes for their G.fast, now at about 100,000 homes passed, but I haven't been able to confirm that. Alternately, there could be problems at Broadcom, the chip vendor. Broadcom operates with military level secrecy, often not releasing details even months after chips are shipping.
Deutsche Telecom once was a world technology leader, but in 2017 they are two years behind schedule building a network seriously inadequate for millions of Germans.