I have a BT Synergy 4500 base unit and three additional handsets. I frequently find that if a handset is removed from its docking station when I try to answer a call from that handset, or even just press any key, the phone cuts out i.e. the display goes blank and it's not possible to take the call. The phones are fully charged and there is a good signal.

According to the user manual the phones record the last 20 numbers that have been received but the handsets often indicate they are storing more numbers than this and when I deleted the call lists the handset seemed not to cut out.

Is this a known fault and is there any sort of firmware update to fix it?

Thanks

It's possible that the batteries are exhausted and not holding charge. I had these symptoms, replaced the batteries with new rechargeables and once they were charged, all was well again.

which replacement batteries did you get for the synergy 4500?

I'm wondering if I can replace the batteries with a higher or lower mAh rating then the 750mAh batteries supplied.....