To facilitate the execution of short (8 h) programmes, we propose ``service observing'' for some easy to observe (e.g. short, single source) programmes with only one set of tunings. Observations are made by the local staff (operators helped by the astronomer-on-duty or by a member of the investigator's institute present at the telescope for his/her own observations). We will try to send you the spectra.30m data files and the two pages of the OBS monitor if your computer allows it (Spain, France or Germany only, so far). This is a passive way of observing, no direct interaction with the telescope through OBS being possible. For this type of observation, we request an acknowledgement of the IRAM staff member's help in the forthcoming publication. Please, if you are interested by this mode of observing, specify it as a ``special requirement'' in the proposal form (IRAM will decide which proposals will actually go to that mode).