Xylem Lab 970 - Manual (Page 39)

Lab 970 Operation
39 ba75558e03 11/2009
The meter is supplied with power via the USB interface.
The RS232 interface enables to transmit data to an external printer.
Note
The relevant interface cable has to be connected if you want to
download data to an interface (USB or RS232).
It is not possible to download data to both interfaces (USB and RS232)
at the same time. After connecting a meter to the USB socket the
RS232 interface is inactive. The RS232 interface is active if no meter is
connected to the USB interface.
CAUTION
The interfaces are not galvanically separated.
When connecting an earthed PC/printer, measurements cannot be
performed in earthed media as incorrect values would result.