Obtaining calibration parameters for a three-port device under test

A device tester that tests a device under test, the device tester comprising:

• a first port;
• a second port;
• and,
• a communication port;
• wherein the device tester communicates to a calibration module through the communication port, instructing the calibration module to change termination values at a port of the calibration module without physical disconnection of the port of the calibration module from a first port of the device under test, the instructing being given during testing of the device under test when a second port of the device under test is connected to the first port of the device tester, when a third port of the device under test is connected to the second port of the device tester, and when the device tester is obtaining calibration parameters for the device under test.

A device tester that tests a device under test, the device tester comprising:

• a communication port means for communicating to a calibration module in order to instruct the calibration module to change termination values at a port of the calibration module without physically disconnecting the port of the calibration module from a first port of the device under test;
• a first port means for connecting to a second port of the device under test;
• and,
• a second port means for connecting to a third port of the device under test;
• wherein the device tester obtains calibration parameters for the device under test.