Rohde&Schwarz: SFL-N (for SFL-T)

[OliverWirthg]

Hello!

I bought an older one and used R & S SFL-N (for R & S SFL-T). I opened the unit SFL-N for cleaning. On the main board of the instrument SFL-N there is a holder for a CR2477N battery. The battery is not in it. Is it necessary to add a battery to the instrument? Or is the battery just related to some extension that the instrument does not have? Thank you for any help and answer!