Welltech ePBX80 V.1.1 - Manual (Page 124)

Welltech Technology Co., Ltd. 124
5.5 Small office IP-PBX application
Figure 1
Notice:
the Epbx80 default codec is G729 (we support codec for
g729/g711a/g711u but just one can be selected to use) so please make sure
your SIP device or SIP App software supports codec for g729.