After you’ve got your USIM, that’s the same shape and size as a regular SIM card, but appears to have and extra pair of connections, get voice working. Takes a day or so. Then, in a regular 3G handset, send an SMS to get the configuration settings into your regular phone. I used my Nokia E71. The settings which came with the USIM didn’t work.
You’ll get the configuration by sending “Make Model” to 58355. In my case this I sent “Nokia E71” to 58355. No quotes, of course.
The settings came protected by a PIN for some reason. Apparently this is 1111 for everyone. Why do is one of those BSNL mysteries. My data connection was up and running in seconds.
Finally cut up the USIM to microsim size, using instructions which you can get elsewhere. Pop it into your iPad, copy the APN across and you should be online.
I believe sending the SMS is what turned my connection on. The APN is bsnlnet without any username or password. But this didn’t work earlier despite my asking for data when I signed up.
Just for the record, the BSNL helpline is 1503, which you call from a BSNL line, of course.
Speedtest shows 2.6 Mbps download and 315 Kbps upload.