<s>
The	O
result	O
of	O
this	O
work	O
is	O
IEC	B-Protocol
60870-5	I-Protocol
.	O
</s>
<s>
Five	O
documents	O
specify	O
the	O
base	O
IEC	B-Protocol
60870-5	I-Protocol
:	O
</s>
<s>
IEC	O
60870-5-101/102/103/104	O
are	O
companion	O
standards	O
generated	O
for	O
basic	O
telecontrol	O
tasks	O
,	O
transmission	O
of	O
integrated	O
totals	O
,	O
data	O
exchange	O
from	O
protection	O
equipment	O
&	O
network	O
access	O
of	O
IEC101	B-Protocol
respectively	O
.	O
</s>
<s>
IEC	B-Protocol
60870-5-101	I-Protocol
 [ IEC101 ] 	O
is	O
a	O
standard	O
for	O
power	O
system	O
monitoring	O
,	O
control	O
&	O
associated	O
communications	O
for	O
telecontrol	O
,	O
teleprotection	O
,	O
and	O
associated	O
telecommunications	O
for	O
electric	O
power	O
systems	O
.	O
</s>
<s>
Link	O
address	O
and	O
ASDU	O
(	O
Application	O
Service	O
Data	O
Unit	O
)	O
addresses	O
are	O
provided	O
for	O
classifying	O
the	O
end	B-Protocol
station	I-Protocol
and	O
different	O
segments	O
under	O
the	O
same	O
.	O
</s>
<s>
The	O
character	O
format	O
of	O
IEC	B-Protocol
101	I-Protocol
uses	O
1	O
bit	O
each	O
for	O
start	O
,	O
stop	O
and	O
parity	O
,	O
as	O
well	O
as	O
8	O
data	O
bits	O
.	O
</s>
<s>
FT1.2	O
(	O
defined	O
in	O
IEC	O
60870-5-1	O
)	O
is	O
used	O
for	O
frame	O
format	O
of	O
IEC	B-Protocol
101	I-Protocol
which	O
is	O
suitable	O
for	O
asynchronous	O
serial	O
communication	O
with	O
Hamming	O
distance	O
of	O
4	O
.	O
</s>
<s>
IEC	B-Protocol
60870-5-103	I-Protocol
 [ IEC103 ] 	O
is	O
a	O
standard	O
for	O
power	O
system	O
control	O
and	O
associated	O
communications	O
.	O
</s>
<s>
IEC	B-Protocol
103	I-Protocol
uses	O
FT1.2	O
(	O
defined	O
in	O
IEC	O
60870-5-1	O
)	O
for	O
frame	O
format	O
having	O
options	O
of	O
Frame	O
with	O
variable	O
length	O
,	O
Frame	O
with	O
fixed	O
length	O
&	O
single	O
character	O
similar	O
to	O
IEC	B-Protocol
101	I-Protocol
.	O
</s>
<s>
However	O
the	O
frame	O
format	O
of	O
IEC	B-Protocol
103	I-Protocol
differs	O
from	O
IEC	B-Protocol
101	I-Protocol
in	O
information	O
object	O
address	O
which	O
is	O
split	O
into	O
function	O
type	O
(	O
ftype	O
)	O
and	O
information	O
number	O
(	O
inumber	O
)	O
in	O
IEC	B-Protocol
103	I-Protocol
.	O
</s>
<s>
Also	O
IEC	B-Protocol
103	I-Protocol
can	O
have	O
only	O
single	O
information	O
object	O
in	O
a	O
frame	O
whereas	O
IEC	B-Protocol
101	I-Protocol
can	O
have	O
multiple	O
information	O
objects	O
.	O
</s>
<s>
Many	O
of	O
the	O
field	O
sizes	O
are	O
also	O
restricted	O
in	O
IEC	B-Protocol
103	I-Protocol
.	O
</s>
<s>
IEC	B-Protocol
60870-5-104	I-Protocol
(	O
IEC	B-Protocol
104	I-Protocol
)	O
protocol	O
is	O
an	O
extension	O
of	O
IEC	B-Protocol
101	I-Protocol
protocol	O
with	O
the	O
changes	O
in	O
transport	O
,	O
network	O
,	O
link	O
&	O
physical	O
layer	O
services	O
to	O
suit	O
the	O
complete	O
network	O
access	O
.	O
</s>
<s>
The	O
standard	O
uses	O
an	O
open	O
TCP/IP	B-Protocol
interface	O
to	O
network	O
to	O
have	O
connectivity	O
to	O
the	O
LAN	B-General_Concept
(	O
Local	B-General_Concept
Area	I-General_Concept
Network	I-General_Concept
)	O
and	O
routers	O
with	O
different	O
facility	O
(	O
ISDN	B-Protocol
,	O
X.25	B-Protocol
,	O
Frame	B-Protocol
Relay	I-Protocol
etc	O
.	O
)	O
</s>
<s>
Application	O
layer	O
of	O
IEC	B-Protocol
104	I-Protocol
is	O
preserved	O
same	O
as	O
that	O
of	O
IEC	B-Protocol
101	I-Protocol
with	O
some	O
of	O
the	O
data	O
types	O
and	O
facilities	O
not	O
used	O
.	O
</s>
<s>
There	O
are	O
two	O
separate	O
link	O
layers	O
defined	O
in	O
the	O
standard	O
,	O
which	O
is	O
suitable	O
for	O
data	O
transfer	O
over	O
Ethernet	O
&	O
serial	O
line	O
(	O
PPP	O
-	O
Point-to-Point	B-Protocol
Protocol	I-Protocol
)	O
.	O
</s>
<s>
The	O
control	O
field	O
data	O
of	O
IEC104	B-Protocol
contains	O
various	O
types	O
of	O
mechanisms	O
for	O
effective	O
handling	O
of	O
network	O
data	O
synchronization	O
.	O
</s>
<s>
The	O
security	O
of	O
IEC	B-Protocol
104	I-Protocol
,	O
by	O
design	O
has	O
been	O
proven	O
to	O
be	O
problematic	O
,	O
as	O
many	O
of	O
the	O
other	O
SCADA	O
protocols	O
developed	O
around	O
the	O
same	O
time	O
.	O
</s>
