Digium cards in the TE series are high-performance, cost effective, digital telephony interfaces and support both E1 and T1 environments. The environments are selectable on a per-card or per-port basis. This feature enables signaling translation between E1 and T1 equipment, and allows inexpensive T1 channel banks to connect with E1 circuits. The bus-mastering TE cards improve I/O speed over slave-only architectures, resulting in reduced CPU usage and increased card density per server. The cards provide the power to interconnect traditional telephony systems with emerging Voice-over IP (VoIP) technologies.