A 19 m long serial cable between the server and the PC
The server cannot be powered on.
Ensure that the serial cable does not hang in the air.
The serial cable hanging in the air serves as an antenna which interferes with signals received by the CPU. The CPU supposes that data transmission starts and receives incorrect data.
If the serial cable is not connected to the PC and hangs in the air, signals at the transmit data (TXD) end are coupled into the receive data (RXD) end of the serial port. In this case, the CPU receives incorrect signals which are like an incorrect command through the serial port during startup. As a result, the CPU cannot start up, and the MM910 cannot issue a command for powering on the compute node.