Here are the English Manuals for the 2638A HYDRA Series III Data Acquisition Unit. 2638A Manuals
The firmware update file with instructions can be found here: Firmware update for 2638A
Fluke DAQ software is no longer available for purchase but if you are using a version that is earlier than 6.0.4, you can use the download link to upgrade your existing software or install it for the first time.
Contact Fluke Electrical Calibration Technical Support at electricalsupport@flukecal.com or create a new Case at my.fluke.com/