  A pseudo $H$-type Lie algebra naturally gives rise to a conformal
pseudo-subriemannian fundamental graded Lie algebras. In this paper we
investigate the prolongations of the associated fundamental graded Lie algebra
and the associated conformal pseudo-subriemannian fundamental graded Lie
algebra. In particular, we show that the prolongation of the associated
conformal pseudo-subriemannian fundamental graded Lie algebra coincides with
that of the associated fundamental graded Lie algebra under some assumptions.
