VDSL try sync on ADSL 2 router?

[PsyCLown]

Hi guys,

So with this rain and lightning I just wanna find out whether a VDSL line, if plugged into an ADSL 2+ router will even attempt to sync / produce any flashing lights or not?

Would like to know if I'm able to use an ADSL router to test if a VDSL line is active or not if my VDSL router were to get struck by lighting.

Thanks,
Psy

 

[atunguyd]

NO - from my observations when I switched to VDSL and ADSL modem will treat it like a line that has no ADSL at all - ther were issues when I switched and we had to switch the line between ADSL and VDSL very often so I saw a lot of this.

I can tell you though that they can switch your VDSL line to ADSL very quickly while you are on the line so in such a situation you could tell them to switch it to ADSL 20mb/s while you get another modem - I had this for a week while they were getting my VDSL working correctly

 

[Masik3R]

Have tested with the Pace and the sync light does blink when forced to ADSL2+. Not sure about other modems though

 

[PsyCLown]

OK, so I managed to do some testing today.

With a VDSL line a normal ADSL 2+ router does not even try and sync. So unfortunately you cannot even do testing with an ADSL 2+ router on a VDSL line. Sigh.

 

[IdlePhaedrus]

OK, so I managed to do some testing today.

With a VDSL line a normal ADSL 2+ router does not even try and sync. So unfortunately you cannot even do testing with an ADSL 2+ router on a VDSL line. Sigh.

This would make sense given that the frequencies used for VDSL and ADSL2+ are different (as pointed out by MickeyD in another post on this in VDSL discussions).

And also why, SNR's on an ADSL2+ router are not a clear indication of the service you might get on a VDSL router.

For example, on the PACE when I was running in ADSL 2+ mode I was getting an upstream SNR of between 6 and 7 and a downstream SNR of between 29 and 31 (depending on the weather ;-)).

Now that I am on a 40Mb VDSL profile my upstream SNR is 32.5 and my downstream SNR is 14.8. Go figure!

Regards
Phaedrus

 

[IdlePhaedrus]

Some more info on frequencies taken from here:

http://forums.anandtech.com/archive/index.php/t-2349854.html

The basic difference is the frequencies and channel width they use from what I can tell with brief reading.

ADSL2+ extends the capability of basic ADSL (http://en.wikipedia.org/wiki/Asymmetric_digital_subscriber_line) by doubling the number of downstream (http://en.wikipedia.org/wiki/Downstream_(computer_science)) channels (http://en.wikipedia.org/wiki/Channel_(communications)). The data rates can be as high as 24 Mbit/s (http://en.wikipedia.org/wiki/Data_rate_units) downstream and up to 1.4 Mbit/s upstream depending on the distance from the DSLAM (http://en.wikipedia.org/wiki/Digital_subscriber_line_access_multiplexer) to the customer's premises.

VDSL2 is an enhancement to very-high-bit-rate digital subscriber line (http://en.wikipedia.org/wiki/Very-high-bit-rate_digital_subscriber_line) (VDSL), Recommendation G.993.1. It permits the transmission of asymmetric and symmetric aggregate data rates up to 200 Mbit/s downstream (http://en.wikipedia.org/wiki/Downstream_(networking)) and upstream (http://en.wikipedia.org/wiki/Upstream_(networking)) on twisted pairs using a bandwidth up to 30 MHz. Bonding (http://en.wikipedia.org/wiki/Channel_bonding) (ITU-T G.998.x) may be used to combine multiple wire pairs to increase available capacity, or extend the copper network's reach.

 

[PsyCLown]

This would make sense given that the frequencies used for VDSL and ADSL2+ are different (as pointed out by MickeyD in another post on this in VDSL discussions).

And also why, SNR's on an ADSL2+ router are not a clear indication of the service you might get on a VDSL router.

For example, on the PACE when I was running in ADSL 2+ mode I was getting an upstream SNR of between 6 and 7 and a downstream SNR of between 29 and 31 (depending on the weather ;-)).

Now that I am on a 40Mb VDSL profile my upstream SNR is 32.5 and my downstream SNR is 14.8. Go figure!

Regards
Phaedrus

I experienced the same thing when moving from ADSL 2+ to VDSL!