Business meals are the time to get to know each other, conversation may wander through many different topics. Payment should be by certified check, approved credit card transaction or with a transfer of funds in a bank. Breakfasts are also the preferred choice to meet, get to know, and exchange information over the potential business deal. It is impolite to split the bill. The telephone is a useful tool to set up appointments and ask some general inquiries, but deals are never closed over the phone.
Telephone is considered an informal means of communication.
It is also recommended that you confirm all appointments over the phone. Cellular phones are pervasive in Mexico. Fax machines are also very common. They are preferred over the phones when dealing important issues. Remember that a spoken commitment in Mexican business culture is never binding.