AT&T 5840 5.8GHz Speakerphone/Answering/Caller ID Answering Machine "cordless phone reads base power" Questions

...charged and base powered up. However all three handsets read out of range or no power at base any suggestions would be appreciated. The base station is defective, that is all that will cause

base reads e4 sometimes reads 88 Base unit display flashing "8" and "88" repeatedly and then after several minuteseventually displays "E4" steadily. none of the keypad inputs register - unit is ...

...phone. These products or equipments include: radio towers, page towers, cellular Phones, other 5.8GHz cordless phones, intercoms, or monitors. If any of these are in the area, they may interfere with ...