Connects via analog phone lines or analog PBX extension lines Phone line powered: no power supply or battery backup needed Push button once to call, then speak hands-free The ETP-110 Analog series is an indoor, hands-free emergency phone for use in locations such as: area of rescue assistance, stairwells, indoor controlled-access areas, senior citizen housing and correctional facilities. Automatically identify attendant of location of calling phone by recorded message. Digital display optional with ETP-TAL. Push button once to call, then speak hands-free. Built-in auto-dialer can dial two numbers: if the first number doesn't answer or is busy, dials second number.