Patent ID: 7337377

Claim:
A method of testing a serial port of a device under test in an automatic test system comprising: (A) evaluating steady-state characteristics of at least one of an actual physical transmit line and an actual physical receive line of the serial port in a production environment; (B) configuring the device under test to generate a serial bit stream and converting said serial bit stream to a direct physical test signal; (C) measuring at least one timing characteristic of the direct physical test signal received with a time measurement circuit; (D) receiving the serial bit stream directly, without benefit of a third or intermediary node, from the transmit line of the serial port of the device under test; (E) transmitting one of the received serial bit stream and a direct input over a physical line directly to the physical receive line of the serial port of the device under test; wherein transmitting includes programming the levels of the transmitted signal to determine whether the device under test responds to input at the programmed levels; and (F) directly monitoring the device under test to determine whether the serial bit stream received by the device under test matches an expected serial bit stream.