FTTC/G.Fast do their own testing from the cab, you can't test much about VDSL/G.Fast from the E-Side/Exchange when the data signal is injected at the cabinet, and filters stop the signal from back tracking into the E-Side.
Not entirely correct.
Some of the current line tests are done from the TAM's in the exchange, for both G.Fast and VDSL2.
Are OpenReach connecting the E-Side on SOGEA lines for giggles?
What do you suppose the purpose of this is without PSTN?
you can't test much about VDSL/G.Fast from the E-Side/Exchange when the data signal is injected at the cabinet, and filters stop the signal from back tracking into the E-Side.
That doesn't prevent tests being carried out from the exchange TAM's kit.
MELT is a DC/narrowband line testing technique that supports the measurements of the electrical line properties at DC, such as resistance, shorts, opens, and capacitance.
MELT operates at DC and at frequencies below the xDSL spectrum, MELT testing can be performed without disrupting broadband services.
Proper testing requires DC coupling of the test circuitry to the line. Not possible on the DSLAM line card because it's AC coupled to the line via a line transformer.
Without sync DSLAM based line testing becomes pretty useless for some tests.
If the DSLAM already does all the VDSL2/G.Fast line tests I ask again why OpenReach are connecting the E-Side to SOGEA connections, on every single SOGEA install.
SOGEA is simply DSL without PSTN.