The LED display control card is frequently disconnected, and it turned out to be the fault of it
We often listen to customer feedback on the use of 4G remote control LED display screens . After a period of time (such as 6 months, 1 year), individual devices appear to go offline frequently or fail to go online. The little brothers we developed specifically address this problem. analyzed in detail.oneSituation statementSome devices have not been online for a long time. Through HDPlayer connection, it is found that the module is normal, but the SIM card cannot be found;Restart the device power, still can not go online, can not find the SIM card;Insert and remove the SIM card, power on again, and the SIM card can be found;Continue to use it for a period of time (for example, about 2 weeks), and the line is dropped again, and the SIM card cannot be found;On-site investigation found that the contacts of the SIM card holder are in good condition, and the shrapnel and plastic structural parts have no deformation;Check the SIM card and find that the gold finger on the surface is seriously oxidized, which affects the contact, as shown in the figure below
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After removing the oxide layer on the surface of the SIM gold finger, it is normal after being installed in the device.twoSummarizeTo sum up, it can be judged that the gold finger of the SIM card is oxidized and leads to poor contact, which makes the control card unable to go online normally. Volatilize and then use), the fundamental solution is to switch to an industrial-grade SIM card with better performance .threeSuggestions for SIM card selectionThe industry-grade MP2 standard SIM card with better coating is selected, and the gold-plated thickness of 15u contacts, the contacts are not easy to be oxidized, and the reliability is higher.
Choose the MP2 standard SIM card ( MP2 is an industrial-grade IoT SIM card).Choose the MS1 chip card provided by our company and weld it directly on the control card, which has good stability and is cheaper. PS:SIM cards are generally divided into 4 categories, MP1, MP2, MS0 and MS1 . MP1 : Conventional mobile phone card (injection molding), the erasing and writing times are 100,000 times, and the working temperature is -25~85°C ; MP2 : industrial-grade mobile phone card (epoxy resin composite ceramics), the erasing and writing times are 500,000 times, and the working temperature is -40~105°C ; MS0 : Conventional chip mobile phone card (epoxy resin) can be erased and written 100,000 times, and the working temperature is -25~85°C MS1 : industrial-grade chip mobile phone card (epoxy resin) with 500,000 erasing and writing times , and the working temperature is -40~105°C .FourOther informationThe SIM card is abnormally inserted, as follows: the module is not inserted correctly, and it is forced into the card holder, which affects the contact; To sum up, it can be judged that the gold finger of the SIM card is oxidized and leads to poor contact, which makes the control card unable to go online normally. use ), it is recommended to use a good quality SIM card.
