Keysight technologies u2781a housing keysight technologies u2781a opt 902 abd this housing for modular usb systems is particularly suitable for use with the keysight technologies u2300a u2500a and u2600a series as an alternative to single operation of the modules on the pc each module can be integrated into the housing so that as many as 6 modules can be accommodated enabling the system to be extended for up to 384 channels br keysight technologies u2781a housing for u2300a series