Professional titles are also very important. Do this even if you know that your business partner is not a licenciado. The telephone is a useful tool to set up appointments and ask some general inquiries, but deals are never closed over the phone. The telephone is considered an informal means of communication. Cellular phones are pervasive in Mexico.
Fax machines are also very common.
They are preferred over the phones when with dealing important issues. Remember that a spoken commitment in Mexican business culture is never binding. Practically all professionals in the service industries have email. In most cases when phoning a Mexican businessperson, you will have to go through 1-3 secretaries before reaching the desired person. These secretaries may not speak English, so have a short sentence in Spanish prepared, asking for the specific person.