Integration testing will do the completion of unit or 
module level Testing.

System testing is nothing but the application meets the 
Required specifications or not

In integration testing individual components are combined 
with other components to make sure the necessarey 
communications, links and data sharing occur properly.

It is not system testing because the components are not 
implemeted in the operating environment.

System testing begins one the modules are integrated enough 
to perform tests in whole system environment.System testing 
can occur in parallel with intergration test, especially 
with the top-down method.

Integration testing means, testing the interface between 
two or more modules(internal interfaces) or interfaces with 
other systems(external interfaces). So in integration 
testing, we will test for the interfaces. From the testing 
point of view, integration testing is black box testing 
appraoch, but if the documents for the functionality is not 
clear, then we will go through the code and test for the 
functionality.
System testing comes after Unit, Component, Intergration 
testing is completed. This is the last chance for finding 
the defects at the offshore, means we wil built-up the 
total system at offshore and test the total system before 
giving to the client.System testing includes both 
functional testing and non-functional testing. The input 
for integration testing is design documents and functional 
documents, whereas for system testing ,the input is user 
requirement document.

intergration test is a test between two or more equipment

 system test is to ensure that the entire intergrated 
equipment  system meet the requirements