hi pix, thank for reply. i gone through the document 3gpp45.003. my doubt is
1) Let us suppose Channel type is speech, channel is speech. for radi ointerface to BTS Conversion is TRAU we can use it..
2) now channel type is data in GSM only. it means Circuit switched data( Fax call ) am doing.
in this case also we need to pack the RTP Packets. what is payload for data transfer.
what type of Conversion used for sending the DATA, radio interface to BTS.