  We present an analysis of X-ray high quality grating spectra of the Seyfert 1
galaxy NGC 5548 using archival Chandra HETGS and LETGS observations for a total
exposure time of 800ks. The continuum emission is well represented by a
powerlaw plus a black-body component. We find that the well known X-ray warm
absorber in this source consists of two different outflow velocity systems.
Recognizing the presence of these kinematically distinct components allows each
system to be fitted independently, each with two absorption components with
different ionization levels. The high velocity system consists of a component
with temperature of 2.7X10^6K and another component with temperature of
5.8X10^5K. The low-velocity system required also two absorbing components, one
with temperature of 5.8X10^5K; the other with lower temperature (3.5X10^4K).
Once these components are considered, the data do not require any further
absorbers. In particular, a model consisting of a continuous radial range of
ionization structures is not required. The two absorbing components in each
velocity system are in pressure equilibrium with each other. This suggests that
each velocity system consists of a multi-phase medium. This is the first time
that different outflow velocity systems have been modelled independently in the
X-ray band for this source. The kinematic components and column densities found
from the X-rays are in agreement with the main kinematic components found in
the UV absorber. This supports the idea that the UV and X-ray absorbing gas is
part of the same phenomenon. NGC 5548 can now be seen to fit in a pattern
established for other warm absorbers: 2 or 3 discrete phases in pressure
equilibrium. There are no remaining cases of a well studied warm absorber in
which a model consisting of a multi-phase medium is not viable.
