Modem: Telenet Tndsl 2120 & Electric Co. ADSL modem/router

[PrabhatKumar]

I have two Tataindicom connection one is 512 Kbps and 256 Kbps with modem Telenet Tndsl 2120 and Electric Co. ADSL modem/router.

I have tested result after interchanging modem:

SNR Margin (Higher margins are good) :->
Line attentuation (High line attentuation is bad) :->

Line of 512 result:
9th May 08 -> Telenet modem: 30.7 down / 9 up
9th May 08 -> Billion Modem: 19.2 down / 9 up

Line of 256 Result:
9th May 08 -> Telenet modem : 9.9 down / 9 up
9th May 08 -> Billion Modem: 6.5 down / 9 up

As my personnel experience Billion Modem as lower performance.

Now my question is :
1. Which modem is better between Telenet Tndsl 2120 & Electric Co. ADSL modem/router ?
2. How can I improve my SNR Margin?

Thanks for any idea!