TG-4E1 Teletechno Media Gateway SIP to 4 ISDN The PRI of E1 is an inexpensive backbone equipment that is specific to working with the PABX X AND LEGACY PBX. Its built-in echo canceller function and voice decode conversion function. Users can flexibly select G.711A / U, G.729, G.723, iLBC a variety of voice decoding and easy-to-complete voice and signal conversion of IP and PSTN. In addition, it provides user-friendly GUI configuration interface, users can freely configure and manage the computer.free and manage the computer