SAP FB70

Why system ask G/L account
While posting customer invoice (FB70) why system asks for G/L account?

As per double entry book keeping rule:
customer is debited
Customer reconciliation a/c is credited

Why one more G/L account on top of Recon a/c, which is posted automatically?

Solution :
* Entry gets posted to Customer a/c through reconciliation account.
You have to give a GL a/c for revenue.

Your entry would be
Dr.Customer (Reconciliation a/c)
Cr.Revenue

* Reconciliation is a fictious entry
so you cannot consider as an entry to be entered by the user.

This rule is derived from the fact that 'we cannot enter/post directly to RECON account'.

That is why system needs a GL account
to make the account balance as zero.

Manual entry could be:
Dr. Customer a/c Dr
Cr. Domestic Sales a/c
(Sales invoiced posted)

Recon entry is automatically made once you post this entry since you have configured your RECON in the IMG.

SAP FBD1 Recurring
Recurring Procedure for A/P & G/L, Recurring Cases , Recurring Transaction Codes 


SAP F.05 Revaluation
Procedure, Reversal, SAPF100 problem, Run twice, B/S Prep. Val, Configuration. 

SAP Clear Open Items SAP Procedure for F-03, FB1S, F-32 , Clear Debit Credit with zero balance open items. 

SAP BDC
SAP Procedure for Batch Data Communication, SM35, Batch Input Sessions, Record BDC, Write Data Transfer Program

SAP FB60
SAP Procedure for FB60, One time Vendor, Park FV60 Procedure, Account assignment template