Transcoding in conferences with meetme

I have the next question about conferences rooms with meetme.conf

All my softphones will use just one codec (GSM) and all my VoIP trunks will use the same codec (GSM). I mean, everybody and everthing will use one CODEC (GSM). But all the calls will be in conferences rooms with meetme.conf.
My question is: Is Asterisk making some TRANSCODING (GSM --> uLaw --> GSM) , for the conferences rooms with meetme.conf?

yes, it decodes the GSM to raw audio for the conferencing, then recodes it to gsm.