qam differences
 

i just wanted to know what the differences are in these qam readings i have seen 64 and 256 qam listings and have seen alot of people talking about them recently i looked on the wiki site about them and it's a bit to techincal for me so could somebody dumb it down for me whats good and bad and what they do.

Re: qam differences
 

All you really want to know is that 256 is a method of getting more efficient use of the existing infrastructure and that Tjets don't like it.

Re: qam differences
 

i looked up tjets only information i get is about paint brushes

Re: qam differences
 

Then try googling "tjet cable modem"

Re: qam differences
 

A Terajet cable modem...

Used, I believe, in ex Telewest areas.

Re: qam differences
 

Have a look at this page. Scroll down to Terayon Terajet TJ210. :)

I'm ex-ntl and I have one, unfortunately lol. :erm:

Re: qam differences
 

so im ok then i have a webstar im not sure what i will get next when my new modem aravies hopefull not one of them im in a qam256 area so im lucky i guess i have never had one and have been in a telewest area for many years i used to have the old moto modem not sure which one it was white and turned grey cream color it had the reset button i beleive on the front

Thanks for the information

Re: qam differences
 

As far as I know, Tjets were only on the then Ntl network.

They were a sturdy and reliable modem but since Ntl removed some service (smpt? or similar?) they weren't able to be interrogated. They also could not go above (IIRC) about 8.3Mbps and as already mentioned were completely screwed up by the introduction of QAM256.

Re: qam differences
 

Is it QAM256 per se or the change in power level that accompanies the introduction of QAM256 ?

Re: qam differences
 

I have no idea and no interest in finding out. All I care about is that teh hardware and services that I pay for and that VM provide work as they should.
I have no doubt that someone will give an explanation if Google can't help.

Re: qam differences
 

SNMP - Simple Network Management Protocol.

Limitation on them was that the ethernet port on them was only capable of 10Mbps operation.

I remember having one, good modem :)

---------- Post added at 20:33 ---------- Previous post was at 20:32 ----------

Power levels at launch were dropped by about 6dB to compensate for the increased loading of the 256QAM constellation. The TJs should have been able to cope with 256QAM but for some reason couldn't get MCNS lock.

Re: qam differences
 

The signal levels increased by about 6dB with the introduction of 256QAM, Not all areas have the 256QAM upgrade, only those that needed it. Was a simple way of increasing data on the Downstream.

No doubt there will be an over the top discussion on whether it be power or signal level and what the difference is.

Re: qam differences
 

Thanks for that info