The 7940 and 7941 are the 20 and 30 amp versions of an older 208 volt Power Distribution Unit. They are capable of being controlled through an ssh or telnet session. The UI is very primitive, but usable.
You can use a local computer, a computer that connects to the Rack PDU or other device through the serial port, to access the control console.
Select a serial port at the local computer, and disable any service that uses that port.
Connect the serial cable (APC part number 940-0144A) to the selected port on the computer and to the configuration port at the Rack PDU.
Run a serial terminal program and configure the selected port for 9600 bps, 8 data bits, no parity, 1 stop bit, and no flow control.
Press ENTER, repeatedly if necessary, to display the User Name prompt. If you are unable to display the User Name prompt, verify the following:
The serial port is not in use by another application.
The terminal settings are correct as specified in step 3.
The correct cable is being used as specified in step 2.
Press the Reset button. The Status LED will flash alternately orange and green. Press the Reset button a second time immediately while the LED is flashing to reset the user name and password to their defaults temporarily.
Press ENTER as many times as necessary to redisplay the User Name prompt, then use the default, apc, for the user name and password. (If you take longer than 30 seconds to log on after the User Name prompt is redisplayed, you must repeat step 5 and log on again.)