“Some ITECH test equipment has a DSUB connector with a standard-breaking 5V TTL connector on it. This is a non-isolatd USB converter for this equipment, for interfacing to a PC.
It is known to work with at least the following models:
ITECH IT6831 DC power supply
ITECH IT8511 electronic load
It should also work with all models in the IT6800 family, as well as several BK precision devices which they appear to be direct copies of.
Note that the A- and -+ versions of these test equipment generally have built-in USB ports that support USBTMC, which is somewhat easier to work with.”