Is the modem-router sensitive to the polarity of the ADSL/VDSL connection?

[gatekeeper]

Is the 8800NL, or indeed any other recent Billion modem-router, ADSL-polarity sensitive?

I'm referring here to the connection between the user's wallplate termination (the NTE5 combo) and the DSL connection on the modem-router, which as you'll appreciate is simply a two-wire affair and uses the centre pair of contacts in the RJ45/RJ11 jack-socket at the wall. (The RJ11 connection, in this context, is I believe a TIA sub-set of the 8-contact RJ45 arrangement). I'm wondering if Billion modem-routers work better with the centre pair used one particular way around.

Normally, the B wire (blue or blue/white) from the exchange or street-cabinet and which is terminated in the wallplate, is connected to pin4 in the wall-mounted RJ45 jack-socket (into which the modem connection is then inserted), and the A wire (white/blue) is connected to pin5 in the RJ45/RJ11 socket, but I've discovered that this is reversed on some arrangements. I've found, for instance, that these two centre connections are reversed when comparing an Openreach Mk3 intermediate faceplate (with incorporated filter) with, say, a Clarity filtered faceplate.

What further confuses the matter is that, over some years now, the various modem-router manufacturers have supplied RJ11 cables that are differently wired; with some, the cable has carried through the pair of wires as straight-through, but with others, the pair is crossed in the cable.

Bear in mind that I'm referring only to the ADSL/VDSL connection pinouts, NOT the telephone pinouts.

I'm just wondering whether the TIA standard for RJ45/RJ11 connectors was changed some years ago and perhaps now the polarity of this pair is deemed immaterial as far as modems are concerned. Is this the case? Certainly, I can remember a time when it was said by 'the experts' that some marques/models of modems were sensitive to ADSL polarity, their performances being more zippy one way around than the other, but does this apply any more?

[gatekeeper]

There having been zero immediate response to this question, I thought I'd trawl the Internet yet again for a lead on this. Once again, I found next to nothing. However, the Openreach SIN498 compliance document 7.1 (http://www.sinet.bt.com/sinet/SINs/pdf/498v7p1.pdf), published earlier this year, does briefly mention this.

In the appropriate sections, it states that physical connection, effectively to a VDSL2/ADSL2+ line, is presented on two middle pins - ie. pins 3 and 4 (RJ11) or pins 4 and 5 (RJ45), pin numbering from the left, looking into the sockets with the contacts uppermost. Polarity is unimportant.