There is no such thing as interleaved depth zero. The number is the number of packets across which a real packet is spread. So a non-interleaved (fast path) line has interleave depth 1.
On Openreach fibre, (I prefer English to American
), you need to look at the Delay line, not the D: line. The same is also true on ADSLx in fact. The Delay line is the number if ms added to your raw latency by DLM.
The current unlocked firmware is G.INP capable. Earlier ones are not. G.INP is only activated on lines that would otherwise have interleaving depth in the hundreds or thousands and usually higher Delays. Get a firmware without it and you would be stuck with the high interleaving if Fast Path was not appropriate.
When G.INP is active on an interleaved FTTC line the normal interleaving depth is 8 but the Delay is zero.
With the HG612 and most other modems G.INP activation is easily spotted by the presence of Bearer 1. Which shows with zero sync but IIRC is 200bps. So rounded to 0kbps.
Kindness isn't going to cure the world of all its awfulness but it's a good place to begin. Daisy Ridley.
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