<s>
In	O
telecommunication	O
,	O
the	O
term	O
summation	B-Error_Name
check	I-Error_Name
(	O
sum	B-Error_Name
check	I-Error_Name
)	O
has	O
the	O
following	O
meanings	O
:	O
</s>
<s>
A	O
checksum	B-Algorithm
based	O
on	O
the	O
formation	O
of	O
the	O
sum	O
of	O
the	O
digits	O
of	O
a	O
numeral	O
.	O
</s>
<s>
A	O
comparison	O
of	O
checksums	B-Algorithm
on	O
the	O
same	O
data	O
on	O
different	O
occasions	O
or	O
on	O
different	O
representations	O
of	O
the	O
data	O
in	O
order	O
to	O
verify	O
data	O
integrity	O
.	O
</s>
