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Former Member
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what is the difference between interface and conversion


Former Member
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Interface: it is a program that performs communication with External system from SAP.

There are two types of interfaces:

1. Inbound Interface: External system sends the data to SAP

2. Outbound Interface: SAP sends the data to External system.

Let's take a scenario:

There are two Systems SAP ERP and Seibel CRM

Scenario1: Whenever an Order is created in Seibel CRM system it has to be transferred to SAP where the Order confirmation, Delivery and Billing will be performed. This can be enabled by using IDOC as inbound interface.

Scenario2: Whenever a New customer is Created in SAP ERP this customer data has to be transferred to Seibel CRM using Outbound IDOC / RFC.

Basically interfaces are implemented using RFC, BAPI, ALE/IDOC.


Migration of data from Legacy system before GO Live (One time data transfer).

So Conversions are always INBOUND interfaces.

Conversions are performed using Batch input(BDC), LSMW and BAPI.

Former Member
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Hi Sir ,

Please have a look below .Hope it is suitable and simpler solution for your question.

Please do reward if useful.


CONVERSION programs are the ones which have one time usage, usually when a legacy system is being replaced by a system like SAP, then the data has to be mapped from the legacy system to SAP system. Here the data to be converted is given on a flat file & is uploaded to SAP tables mostly using LSMW only. Conversions programs are BDC,BAPI and LSMW programs in which you upload all the related tables from the flat files.Those are one time programs.

Interface programs are those programs in which you fetch the data from the application server and process on theose data.These are helpful when you have to run any program in the backgroup when the presentation server is not working.

INTERFACE programs are the ones which are run at regular intervals, say weekly, monthly or even daily. Here the legacy system continues to co-exist along with SAP system, the legacy system might be useful for certain functionalities but the data might have to run thru SAP transactions for complex data maintenance at regular intervals.

In Simple

CONVERSIONS : Converting Legacy System DATA into a flat file

INTERFACES : Converting Flat File into SAP

Conversion Program

Interface Program

Reward Points if Useful

Former Member
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Actually conversion means from non-sap to sap (one way communication)

Interface means from non-sap to sap as well as sap to non-sap (Two way communciation)

and interface can used in sap to sap scenarios also.