I've posted about this before but I can't remember how to do it. My broadband has recently reverted to INTERLEAVED from FAST and I would like to have it changed back. I had no issues with it before and I found the low ping great for gaming and even surfing.
Here are my stats:
|DSL Modulation Mode:||G.992.5 (ADSL2+)|
|DSL Path Mode:||INTERLEAVED|
|Downstream Rate:||20150 Kbps|
|Upstream Rate:||1095 Kbps|
|Downstream Margin:||3 db|
|Upstream Margin:||6 db|
|Downstream Line Attenuation:||13|
|Upstream Line Attenuation:||10|
|Downstream Transmit Power:||20|
|Upstream Transmit Power:||10|
The change is automatic, you cannot do it yourself. Interleaved is the preferred setting as it introduces error correction.
If you provide your full ADSL Statistics then the error counters will be shown, and you will see the reason.