You tell your sim to call someone, and there's that friggin' message that the target sim has no phone, and that you can't call sims that have no phone.
Now you can either quit the current household, move into the target sim's household (if they have one) and buy them a phone, or you can use some cheats to get that sim over, and slip a cell phone in their pocket... Rather annoying, isn't it?
No more of that! Phones for All simply pretends that all teens and older that do NOT live at the current lot, own a cell phone. So, as long as the target isn't a child, and you know them, you can call them, ALWAYS! Whether they really have a phone or not!
NOTE: Since cell phones were introduced in the University EP, you need to have at least UNI or one later EP/SP installed for this mod to work. Base Game just won't cut it.
UPDATE: Februari 15, 2012: The initial version had a 'feature'; due to an omission on my part, it treated sims of the current family as if they ALSO had cell phones. This was nice when the sim was called, because you could see their butt ring, even if they did NOT have a cell phone. But it was not so nice when you wanted them to call someone, because they didn't actually have the device. Also, it prevented you from using cheats to actually give them a cell phone! The new version addresses this issue!
File Updated 15-02-2012