Back in 2006, UMTS was still a more or less new kid on the block and during my travels I often experienced interoperability issues with devices working well in their home network but not so well in other networks when traveling abroad. Here's an example. Things have considerably improved since then but still every now and then things go wrong. Here are some recent observations from Italy:
- My now already somewhat old N95 just won't stay in the WIND network in manual selection mode. At some point it looses the network and miraculously reappears on the TIM network. I've never seen before that the device would just go to another network while in manual network selection mode. Definitely a first.
- My default 7.2 Mbit/s 3G USB stick, which I would consider very stable in my German home network, every now and then completely looses the connection to the WIND network in Italy despite good network coverage and no movement and goes into network search mode. Quite incredible. Also it sometimes completely hangs and doesn't react anymore. Only a power cycle brings it back to live.
- It seems the stick quite frequently has a problem to go from Idle to Cell-DCH state. In such cases, the stick tries for about 30 seconds to change the state before it succeeds and data flows again. Totally unacceptable. The only thing that helps is a constant ping which keeps the connection at least in Cell-FACH state.
Luckily I still have my somewhat old Huawei E-220 with me. Despite being a bit bulky and only HSDPA 3.6 Mbit/s capable (no HSUPA), this is the most stable piece of 3G hardware I ever had and it displays non of the issues described above.