Help Under "System select", does "home only" prevent roaming for voice calls?

[Johnny Cakes]

Under "System select", does "home only" prevent roaming for voice calls?

 

[kahale]

i think so. tho when i had it set to auto it would always switch me to 2g at random even tho 3g is available. i have to reboot to fix it. i just set it to home. no problems since.