What environmental factors may have an effect on the AT calibration system and communications with testers?
In one documented case there was a spot welder near the AT Calibration PC and the GPIB cable to the HP3458 DVM was getting interference when the AT Calibration software reached the high voltage portion of the test. The AT3600 and PC were moved away from the welder for calibration and the HP3458 communications problem was resolved.
In general, when high voltage and/or high power systems are running close by communications cables (especially un shielded RS232 cables) there is an increased risk of cross talk interference between the communication cables and high power systems. This can cause communication errors.
Also, if cables are extended ensure that the maximum allowable length for RS232 cables are not exceeded, this also may cause interference pick up and communication errors.