Some dialing rules changed from US to Mexican cell phone ONLY.

Now you have to include a 1 before the area code

Old way:     011 52  638 107 4894

NEW way:  011 52 1 638 107 4894

Also, to dial to a MEXICAN CEL OUT OF TOWN:
Wathever the area code is, now you have to dial 045 before it ( I am
using Caborca, and my phone # as an example)

Old way:             01 637 107 4894

NEW WAY:       045 637 107 4894

Aparently, now the one who calls, pays and doesn’t eat the credit of
the receiver. Before, both caller and receiver paid and were eating
each other’s credit……