DDBJ can not accept only assembled EST sequences. However, DDBJ can accept EST assembled sequences as TSA with original (i.e. before assemble) sequence data. See also Data Submission form Transcriptome Project.
When original sequence data (primary entries) are generated from Next Generation Sequencers, submit to DDBJ sequence Read Archive (DRA), from traditional sequencers, submit as EST via Mass Submission System (MSS).
Then, DDBJ can accept assembled sequences (both de novo and reference mapping) as TSA through MSS.