SIM cards

• For reliability, use a SIM card with gold-plated contacts. Gold-plated contacts provide protection against oxidation, which can occur over time and with exposure to humidity in the air.

• Vibration in the application environment is the most common cause of SIM card failure, which results in loss of communications with the mobile network.

• The specific failure mode is fretting between the contacts of the SIM card and the card holder. For highest reliability, Digi strongly recommends that you apply a thin layer of dielectric grease to the SIM contacts prior to installing the SIM card. You need only to apply enough dielectric grease that the mating area of the contacts is protected from exposure to air and humidity.