The CISCO ATA-187 is an analog telephone adapter designed for VoIP applications, featuring 2 FXS ports for phone connections and 1 Ethernet port. It operates within a temperature range of 41°F to 113°F, with power requirements of 100VAC minimum and 240VAC maximum, delivering 12VDC at 1A. The device produces 34 DBA noise levels and supports SIP protocol, utilizing an external power adapter compatible with 120/230 VAC.