Noise margin

[Philip_L]

Hi

Just wanted to add an update here. I'm now using the 7800DX and I'm seeing gaps/tones disappearing and reappearing. No longer does the line degrade and lose margin because of shutdown tones, but it certainly did with the 7800N and all things are equal apart from the two routers.

Regards

Phil

[maximod]

Hi Phil,
That sounds interesting, seems to do what the 2700hgv did !
Is the 7800DX the full model number, or it it the "L" version ?

It would be nice if Billion could get the 7800n to do this with a firmware upgrade (wishful thinking)

If i order this model i want to be sure i buy the right one.

Thanks,
Paul.

[billion_fan]

Hi Phil,
That sounds interesting, seems to do what the 2700hgv did !
Is the 7800DX the full model number, or it it the "L" version ?

It would be nice if Billion could get the 7800n to do this with a firmware upgrade (wishful thinking)

If i order this model i want to be sure i buy the right one.

Thanks,
Paul.

Bipac 7800DXL - Lite version without VPN
Bipac 7800DX - Full version with VPN support
Bipac 7800VDOZ - Full version with VPN support and VOIP ports

[Philip_L]

Hi

Hi Phil,
That sounds interesting, seems to do what the 2700hgv did !
Is the 7800DX the full model number, or it it the "L" version ?

It would be nice if Billion could get the 7800n to do this with a firmware upgrade (wishful thinking)

If i order this model i want to be sure i buy the right one.

Thanks,
Paul.

It is the 7800DX I'm using, that is the full number. As posted by billion_fan there are others in the series, they are all essentially identical internally, with the non VoIP models just having half the circuit board unpopulated.

It must be a difference in the modem firmware driver compared to the 7800N as they are both Broadcom based. It would be great if Billion could update the 7800N to the same ADSL driver, although it might not be that simple if the driver has dependencies on other parts of the firmware.

It should be noted my line has SRA enabled (not sure if that is making a difference to recovered tones), however even though the 7800N did seamlessly adjust sync speed, tones were never recovered with SRA and I lost the "tail" of high frequency tones over a day, not so with the DX where gaps fill in again. I had actually thought the DX must have been dropping the line often and resync'ing hence seeing gaps recovered, but on checking via the ISP portal which records dropped sync and sessions, and with the router logs, it shows no drop. I've also been streaming during times gaps have recovered and there is definitely no loss in sync.

There is a difference how 7800N and the 7800DX behave in terms of modem performance, so Broadcom have changed something:

With the 7800N (and an older Netgear I tried) there was a constantly adjusted sync speed via SRA, maybe every few minutes it was plus or minus 20-100KBs difference.
The 7800DX hardly ever SRAs. It will first sync a few hundred KBs lower than where it will eventually end up after a few hours by making a few upward SRA adjustments. On several occasions it's ended adjusting up to exactly the same sync speed where it sits quite happily.

Of course this may just be a lucky meeting of a two Broadcom chips at either end with complimentary firmware versions, so no guarantees.

Sorry for not believing you originally that such things could happen

Hope that helps.

(I'm using the modifed DMT program to chart and view the tones, although the 7800DX will work with the un-modified version of the same program.)

Regards

Phil

[maximod]

Thanks billion_fan for the detailed information regarding the versions of 7800 series.

Philip, i assume you are in the UK, i did not know sra was used here.

As i am on a long line with 57-59db attenuation, the higher tones really do drop back somewhat, so if the 7800dx would re use higher tones that were mapped out over night, and would so look at re using them the next day, would allow me to maintain a far more stable long term max sync rate.

I am sure hell would freeze over before i am ever likely to get fttc here

Due to the weak broadband signal here, i have done various things to reduce background noise interference, to get the best sync rate possible.
The sm psu that came with the 7800n causes reduced bitloading, due to sm nature of the supply, i instead feed the 7800n with a 12v battery on float charge.
The other advantage here is no re sync due to a mains outage, which at times can be 5 times a day, at other times can be fine for months.

All interesting stuff!

Paul.

[Philip_L]

Hi

Yes in the UK and if you are lucky you can get SRA enabled on O2 Wholesale provider lines and BeThere/O2 did a trail of SRA, also UKOnline did SRA by individual request but they have long gone.

Something that may affect you is the new series are using 15 volts and not 12 volts at the power in, although they may work fine with 12 volts given that I suspect 15 volts is immediately dropped down to 5 volts and less.

Don't forget if you order on line you can return it within 7 days if it isn't suitable for your needs.

Let us know how you get on.

Regards

Phil

[MagpulACR]

@Philip_L

Which older Netgears have you used? Would you say the 7800DX is the best performing modem/router you have used for sync speed/stability? Is it faster/more stable?

I'm looking for a new modem/router or modem only for my adsl2+ service (can't get FTTC yet 'for a while') via 'Be/O2W'.

I was looking at one with the BCM6361 chipset, it appears to be very good from what i have read.

Oh and my current setup is a Huawei HG612 Bridged to a Asus RT-N66U

[tinytim]

Oh and my current setup is a Huawei HG612 Bridged to a Asus RT-N66U

Nothing wrong with that combination as that's what I'm currently running on Infinity.