In the past I have usually used at least one SIM card for voice telephony and a separate one for Internet access. I never liked this approach very much and always looked for ways to combine the two. These days, combined voice and data offers on a single SIM have improved so I've been using my Nokia N95 for voice telephony, Internet access directly form the phone and as a modem for notebook Internet access over the past couple of weeks now. Interestingly enough, it turns out that the combined SIM is not as convenient as I always thought.
There are a number of reasons:
- When a voice call comes I have the option to remove the cable from the phone or to have my movement restricted by the cable while being on the phone. Both feel uncomfortable as I don't want to loose the Internet connection while I am on the phone but also often don't want to remain in front of the computer.
- During phone calls, the connection is often handed over from the 3G network to 2G network. This cuts the Internet connection since most GSM networks are still not Dual Transfer Mode (DTM) capable. This can be fixed by locking the phone into 3G only mode. This has the disadvantage, however, that I have to reset the network mode later when I am on the move again as 3G network coverage is still not in all places where 2G coverage can be found.
- Unlike others, Nokia mobiles still don't charge over the USB cable. Thus, the battery drains very quickly if no power socket is available, which is usually the case at airports and other public places.
Bluetooth might be an alternative for the USB cable. The power cable would still be required but that can be disconnected easly for a phone call. For now, version 2.x with it's theoretical top speed of around 2-3 MBit/s is still fast enough for most HSPA connections. With HSPA speeds continuously rising, that won't hold for much longer.