Spirent Communications Abacus 5000 – allows testing TDM, VoIP and TDM / VoIP systems during call load with different types of signaling protocols used in TDM networks (4x E1), including SS7 protocol, and IP networks (2x 1Gbps optical interface). The device allows emulating up to 20,000 endpoints with SIP signaling and automatically generate, terminated and evaluate (3 tones, PESQ) calls.