<s>
is	O
the	O
data	O
transfer	O
bus	B-General_Concept
of	O
the	O
proprietary	O
Hewlett	O
Packard	O
architecture	O
HP	B-Device
3000	I-Device
and	O
later	O
many	O
variants	O
of	O
the	O
HP	O
9000	O
series	O
of	O
UNIX	O
systems	O
.	O
</s>
<s>
This	O
bus	B-General_Concept
has	O
a	O
32-bit	O
data	O
path	O
with	O
an	O
8	O
MHz	O
clock	O
.	O
</s>
<s>
It	O
supports	O
a	O
maximum	O
transfer	O
rate	O
of	O
23	O
MB/s	O
in	O
burst	B-Architecture
mode	I-Architecture
.	O
</s>
<s>
That	O
bus	B-General_Concept
was	O
also	O
used	O
to	O
directly	O
support	O
the	O
Programmable	O
Serial	O
Interface	O
(	O
PSI	O
)	O
cards	O
,	O
which	O
offered	O
multi-protocol	O
support	O
for	O
networking	O
,	O
notably	O
IBM	B-Protocol
Bisync	I-Protocol
and	O
similar	O
systems.The	O
920	O
,	O
922	O
and	O
932	O
series	O
supported	O
up	O
to	O
three	O
PSI	O
cards	O
,	O
and	O
up	O
to	O
five	O
cards	O
in	O
the	O
948	O
and	O
958	O
series	O
.	O
</s>
