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[Weaver]

I am absolutely full of morphine, a double shot tonight and that on top of various other drugs. So it was all a bit blurry trying to read the earlier thread.     

[Weaver]

Bearing in mind that Kitz drew our attention to the forbidding of upstream G.998.4 in the case of G.992.3 https://forum.kitz.co.uk/index.php/topic,23280.msg395111.html#msg395111 although ejs also reminds us that PhyR is not G.998.4, I still don’t understand why the standards for G.992.3 or the practical choices in PhyR don’t support upstream L2ReTX in G.992.3?

You have to write the code anyway don’t you, for the other case, G.993.2 surely, so why not use it for G.992.3 as well ? For PhyR you can make your own modem models look better than the competitors’ by an even greater margin?

[ejs]

I never found anything definitive that states upstream PhyR does not exist for ADSL2/2+. Perhaps it is just not enabled for your line.

I can speculate about the reasons why the designers didn't do upstream retransmission for ADSL2/2+:

• The primary motivation for retransmission was for the delivery of IPTV, a downstream only service.
• The ADSL2/2+ upstream uses lower frequencies than the downstream, which have lower attenuation and maybe suffers less from interference anyway. This is unlike the VDSL2 upstream, where most of the upstream bandwidth comes from high frequency bands.

[Weaver]

Thank you for your insight