  We analyse the 30 October, 2004, X1.2/SF solar event that occurred in AR
10691 (N13 W18) at around 11:44 UT. Observations at 212 and 405 GHz of the
Solar Submillimeter Telescope (SST), with high time resolution (5 ms), show an
intense impulsive burst followed by a long-lasting thermal phase. EUV images
from the Extreme Ultraviolet Imaging Telescope (SOHO/EIT) are used to identify
the possible emitting sources. Data from the Radio Solar Telescope Network
(RSTN) complement our spectral observations below 15 GHz. During the impulsive
phase the turnover frequency is above 15.4 GHz. The long-lasting phase is
analysed in terms of thermal emission and compared with GOES observations. From
the ratio between the two GOES soft X-ray bands, we derive the temperature and
emission measure, which is used to estimate the free-free submillimeter flux
density. Good temporal agreement is found between the estimated and observed
profiles, however the former is larger than the latter.
