2 Channels Telephone Extenders -Tel over Fiber Optic PCM Voice with Ethernet FC
Ringing frequency: 17~60HZ. Ringing frequency: 22~28HZ. Single-mode and multi-mode adaptive, single FC interface (SC optional). Ethernet RJ45 port specifications Bell flow: AC90 plus or minus 15V. Balanced noise: ≤63.7dBmop.