- Alternate action call button to place or cancel a call- Intelligent call progress detection for automatic hang-up on CPC silence busy signal or time out- Telephone line powered- Weather resistant features: mylar speaker gaskets internally sealed push button switch UV stable exterior enamel coated PCB- Adjustable microphone and speaker volume- Programmable maximum call length- Selectable auto-answer feature allows remote monitoring- Two way handsfree communication- Programmable VOX (mic/speaker) swi