[NTLUG:Discuss] OT battery substitute

[Fred James]

Brian Koontz wrote:
> On Sat, Apr 30, 2011 at 03:36:20PM -0500, Levi Darby wrote:
>   
>> A 6v adapter should be fine.  Just make sure not to use too high of
>> current.  I don't recommend going higher than 400 mA though.
>>     
>
> The adapter will supply the current needed for the device, so you'll
> want an adapter rated at a current higher than the draw of your
> device.  Keep in mind that a 6V adapter will read 6+ volts "unloaded"
> and then sometimes drop quite a bit under load. There is an off-chance
> you're running an adapter that doesn't meet the current requirements
> of the device.  If that's the case, the voltage will drop quite a bit,
> which could cause the problems you're seeing.
>
> You should be reading the adapter voltage while it's under load,
> plugged into the device.  
>
> BTW, the hum you hear is RF interference from the AC side of the
> adapter.  You can try finding an old iron toroid or power line filter
> and wrapping the output line a few times around it.  Wall warts are
> cheap and cheaply made.
>
>   --Brian
>   
The 5V DC adapter is now installed and the result is the same as the 6V 
DC adapter ... constant call light and buzz in receiver, while all other 
operational features remain unaltered from what is desired.

Thank you all for your help ... I shall try to find the power line 
filters suggested ... I may be able to live with the constant light.

I have tested the operation with the adapter plugged into wall current, 
and with the adapter plugged into UPS current, so either the UPS isn't 
filtering, the UPS isn't filtering enough, or there isn't any difference 
for the phone.
Regards
Fred James