Darwin Mag has an interesting argument on why businesses should avoid going completely wireless even if the number portability is in place. Sometimes, PBX is a good thing.

bq. Kevin Duffy-Deno, director of analytical services at PriMetrica, a telecommunications consulting firm, says there are, at the moment, some good reasons for a business to hang on to a land line. One, says Duffy-Deno, land lines work with FAX machines, and wireless phones don’t, so if you give up your land line you kiss your FAX good-bye. More importantly for businesses, he says, the wireless industry has yet to come with efficient in-house call routing services, like PBX or Centrex.