My old no. does not connect to 120.XX seriesIt only connects to 202,203 or 59 series. (Hence I use it in data card)But my new no. connects to 59 or 120 series. (I use it as my main no. and light mobile internet usage)The 202 and 203 are oldest IP series MTNL used for dial up connections. Now since dialup is used very less, MTNL has added those IP's to 3G services. The way routing is done, the less server load enables better pings and speeds on those series.