  We study parabolically induced representations for $GSpin_m(F)$ with $F$ a
$p$--adic field of characteristic zero. The Knapp-Stein $R$--groups are
described and shown to be elementary two groups. We show the associated cocycle
is trivial proving multiplicity one for induced representations. We classify
the elliptic tempered spectrum. For $GSpin_{2n+1}(F)$, we describe the Arthur
(Endoscopic) $R$--group attached to Langlands parameters, and show these are
isomorphic to the corresponding Knapp-Stein $R$--groups.
