Why USB modular instruments (U272XA, U2741A, U2751A and U2761A) is not detectable by E5813A?

This issue happened because the PC is failed to enumerate the USB modular instrument. An interim solution for this issue is establish the connection between the USB modular Instrument and the PC directly, and then disconnect the USB modular instrument from the PC (while it’s still powered-on), and subsequently connected to a powered-on LAN-USB interface, then the USB modular Instrument will maintain its connectivity to the PC through the LAN-USB interface.