Please help,how to get serial login?

On other unix system i use enable ttya1 or vi inittab
and add getty line with port and serial.
Here i try
first serials

lsdev -Cc adapter | grep -i serial
vsa0      Disponibile       Adattatore seriale virtuale LPAR
vsa1      Disponibile       Adattatore seriale virtuale LPAR
penable vty0
init q

But no serial login appears.
Why?

---------- Post updated at 01:18 PM ---------- Previous update was at 11:26 AM ----------

Solution found on net

chdev -l vty0 -a runmodes='hupcl,cread,brkint,icrnl,opost,tab3,onlcr,isig,icanon,echo,echoe,echok,echoctl,echoke,imaxbel,iexten,clocal' -a logmodes='hupcl,cread,echoe,cs8,clocal' -P

and enable login

chdev -l vty0 -a login=enable

and enable vty0

penable vty0

and edit inittab and set

vty0:2:respawn:/usr/sbin/getty /dev/vty0

in inittab
Works fine