Panasonic KX-TD816 User Manual page 210

5.5 Specifications
Characteristics
Item
Maximum Number of Station
Instruments per Line
Ring Voltage
Environmental Requirements
210
1 or 2 by Parallel or eXtra Device Port Connection
70 Vrms at 25 Hz depending on the ringing load
0 °C - 40 °C, 10 % - 90 % relative humidity
Description
Appendix