Something fairly catastrophic happened to my long-time stable line before 7:50pm Friday giving DS speedtests of just of 60Mbps; afterwards, 40Mbps.I have a (perhaps two) major crosstalk disturbers that has a similar impact 6-7db each. Overall I have lost 40% due to crosstalk and as I am on ECI cabinet I do not know if it can worse - I hope not but not convinced unless they get GINP/3db working for at least a little compensation.
That fits, WWWombat. The diagnosis/suggestion of cross talk is far beyond me, but in the past couple of months I had noticed that my "max attainable", which used to be well above 70Mbps (on 3Dec2016 it was 75,208Kbps), had been drifting lower and lower. Earlier this month it was now and then just below my actual sync rate. (Which puzzled and alarmed me.)
I cannot remember/recover the date now (early March?), but there was some work on my cabinet -- something to do with "ducting", perhaps, or resituating the cables to the PCP on the other side of the road. Great, I thought; things will improve. Fat chance. However, this is just empty speculation. I guess it is simply that several new lines were crammed into the cabinet, as BT's assets get increasingly sweaty.
...Fibre (VDSL) uses high frequencies (up to 30Mhz in some cases but usually 17Mhz as is your case)(from snadge)
I'm a little amazed that wires originally intended to carry audio up to c. 8Khz can support this.
The PSTN actually uses less than half that bandwidth, 300 - 4000 Hz, to be precise.
Even less...
When I wrote code for carrying traffic over digital transmission systems (DASS2, Q931, ISDN etc), you had to specify what kind of bearer circuit was being carried on the 64kbps digital path ... and the regular telephony one was known as "3.1kHz", representing 300Hz - 3.4kHz.
Those numbers have stuck in my brain for nearly 30 years.
SNRM 5.9 / 7.1
DS/US attainable: 79904/22572
DS/US actual: 69594/19999
PWR: 13.8 / 7.4
ATTN(DS) 18.0
INT 1363 (??)/ OFF
The BT engineer just left. He was here from 1pm to gone 4:30, up poles, in PCP, head scratching, running several tests. Noisy copper. Line swap, DLM reset. Left, saying (1) DS now stable at 67, (2) he'd keep an eye on it as he wasn't 100% happy about where the noise was coming from. Supernaturally diligent and pleasant guy. Explained everything he was doing. Can I send Openreach some kind of unsolicited glowing testimonial? Sadly, I've forgotten already his second name. Ross someone, from Yorkshire.
I think this got lost (reduced):
to burakkat: thanks much for the engineer big-up link. I hope I did it effectively. Stellar individual.
to WWWombat: thanks advice. To anyone: very grateful for any links and advice about reducing sync speed to avoid new problems now (on HG612/Huawei).
Pi.
There's quite a difference in responsiveness between "INT 16" and "INT 8"; its only when downloading an operating-system or a movie that throughput matters, and then only a little.