Reasons for No Power Supply in Digital Cash Register POS Hardware COM Port

The power supply of the COM port is mainly powered by the motherboard, usually through a +5V or +12V power line. Sunany digital cash register POS hardware will set the COM port to no power when they leave the factory. Some models can be powered in the BIOS settings, while some models require jumper settings to enable.

When the COM port is powered, it can provide power to connected external devices such as receipt printers, cash drawers, and other peripherals, which can help eliminate the need for additional power adapters. But sometimes we will encounter the situation that the Digital cash register POS hardware COM port has no power supply. Sunany summarizes some reasons for it and hopes to help you troubleshoot the problem.

1. As mentioned earlier, the COM port mainly relies on the motherboard power supply. If the power supply circuit components on the motherboard, such as capacitors and resistors, are overloaded or aged and damaged, then the COM port cannot be powered.

2. COM port usually requires a level conversion chip to achieve reliable communication. Level conversion chip (such as MAX232) is responsible for converting TTL level to RS-232 level. If the chip is damaged, it may also cause the COM port to have no power supply.

3. If you are sure that the COM port power is turned on, but there is a problem with no power, we can also check the BIOS settings to ensure that the power supply of the COM port is not disabled in the BIOS settings.

4. In order to save power, the power management settings of the operating system may turn off the power of the COM port when the digital cash register POS hardware is on standby or hibernation. At the time, you need to check the power management settings to ensure that the power supply of the COM port is not turned off.

Sunany digital cash register POS hardware is usually equipped with 1 to 2 COM ports. By default, we will set it to no power. If you need to modify the settings when purchasing our digital cash register POS hardware, please inform us in advance.